Term Index (T)

Astrophysics (Index)

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Term Index (T)

Astrophysical terms and names of things beginning with the letter T.

T2 T4 TA TB TC TD TE TF TG TH TI TJ TK TL TM TN TO TP TR TS TT TU TV TW TX TY TZ

T (T-type star): brown dwarf with a temperature in the vicinity of 1000 K
T (tesla): unit of magnetic flux density
t (timescale): general length of time something takes
T association: stellar association with T-Tauri stars
- stellar association: like a large open cluster but even less tightly bound
T dwarf (T-type star): brown dwarf with a temperature in the vicinity of 1000 K
- brown dwarf: star-like object with less mass than a star
T Pyx (T Pyxidis): well-known recurrent nova
T Pyxidis: well-known recurrent nova
T Tau (T Tauri): variable star taken as example of young star
T Tau N

T Tauri: variable star taken as example of young star

T Tau Sa

T Tauri: variable star taken as example of young star

T Tau Sb

T Tauri: variable star taken as example of young star

T Tauri: variable star taken as example of young star
Télescope à Action Rapide pour les Objets Transitoires (TAROT): network of telescopes to catch GRB optical counterparts
TŻO (Thorne-Żytkow object): giant star with a neutron star at its center
T-1: see Palomar-Leiden Survey
T-2: see Palomar-Leiden Survey
T-3: see Palomar-Leiden Survey
T-class: see T-type star
T-class star (T-type star): brown dwarf with a temperature in the vicinity of 1000 K
T-mode: see CMB polarization
T-ReCS: see Gemini Observatory
T-Tauri star: type of variable pre-main-sequence star
- Herbig AeBe star: type of pre-main-sequence star more massive than a T-Tauri star
- pre-main-sequence star: star not yet with a nuclear reaction
- T association: stellar association with T-Tauri stars
T-type star: brown dwarf with a temperature in the vicinity of 1000 K
T2CAM: see Lucy
T4 APT (T4 Automated Photometric Telescope): automated 75-cm telescope to a long-term star monitoring survey
T4 Automated Photometric Telescope: automated 75-cm telescope to a long-term star monitoring survey
t₀: see Lambda-CDM model
t₀: see seeing
T_B (brightness temperature): temperature of an equivalent black body in terms of spectral radiance
T_BB (effective temperature): temperature of an equivalent black body in terms of total radiation
T_C (color temperature): temperature-measure of a source based on a color index
T_e (elastic thickness): measure of the thickness of a sagging layer of a planet surface
T_eff (effective temperature): temperature of an equivalent black body in terms of total radiation
T_eph

time standard: method of designating points in time and quantifying time periods

T_eq (equilibrium temperature): temperature a planet would have if it were an externally-heated black body
t_H (Hubble time): approximation of the age of the universe
T_n: see elastic thickness
T_Vir: see virial theorem
TA (Telescope Array Project): cosmic-ray observatory aiming for extremely energetic particles
Tabby's Star (KIC 8462852): star with unusual variations
Table Mountain Facility (Table Mountain Observatory): NASA observatory near Los Angeles
Table Mountain Observatory: NASA observatory near Los Angeles
TAC: telescope allocation committee
TAC: time allocation committee (for telescopes)
TAC 1.0: see USNO Twin Astrograph
TAC 2.0: see USNO Twin Astrograph
tadpole orbit

halo orbit: type of orbit around an unstable Lagrangian point

TAI: see Terrestrial Time
TAIGA experiment (Tunka experiment): Russian Cherenkov detector aimed at cosmic rays and gamma rays
tail: see comet
- comet planet: planet with some characteristics of a comet
TAIPAN: multi-object spectrograph with robot fiber-positioner
TAIPAN: see UK Schmidt Telescope
- fiber positioner: machine to set up fibers in multi-object spectrograph
Taipan Galaxy Survey

TAIPAN: multi-object spectrograph with robot fiber-positioner

Taiwan

Academia Sinica Institute of Astronomy and Astrophysics: Taiwanese astrophysics research organization

TALE: see Telescope Array Project
TAM: non-gray-RT 3D model of Titan's atmosphere
TAMA 300: small prototype gravitational wave detector in Japan
TAMBO: concept for neutrino detector in valley in Peru
TAMS: see zero-age main sequence
- post-main-sequence star: star evolved beyond its main sequence phase
Tamura: see rare designator prefixes
tangential velocity: see radial velocity
TAO (University of Tokyo Atacama Observatory): observatory for a 6.5 m infrared telescope under construction
- Atacama Desert: Chilean high-altitude, dry plateau with numerous observatories
- Llano de Chajnantor Observatory: group of observatories on a high plateau of the Atacama Desert
TAP: see Taurus-Auriga Complex
- Fly's Eye: 1980s cosmic-ray observatory
- High Resolution Fly's Eye: 1990s-2000s cosmic-ray observatory
TAR (traditional approximation of rotation): approximation of waves on a rotating body
TARA: see Telescope Array Project
Tarantula Nebula (30 Doradus): HI region in LMC
- VLT-FLAMES Tarantula Survey: VLT spectroscopic survey of massive stars
TAROT: network of telescopes to catch GRB optical counterparts
TAROT telescope

La Silla Observatory: Atacama-desert observatory run by ESO

task

task-based parallelism: breaking a computation into tasks that can be run in parallel

task-based parallelism: breaking a computation into tasks that can be run in parallel
TASS (The Amateur Sky Survey): amateur comet and variable-star search survey
TASV: see rare designator prefixes
Tata Institute of Fundamental Research - India: Indian math and science research institute
TAU (Thousand Astronomical Units): 1980s plan for space probe to travel 1000 AU over 50 years
Tau: see Tau-REx
tau: see lepton
- standard model: model of elementary particles including quarks
- supersymmetry: extension to standard model of particle physics
- TAMBO: concept for neutrino detector in valley in Peru
- tau neutrino: neutrino flavor that becomes a tau particle during interactions
Tau Air Shower Mountain-Based Observatory (TAMBO): concept for neutrino detector in valley in Peru
tau neutrino: neutrino flavor that becomes a tau particle during interactions
- flavor: subtype of some type of particle
- lepton: elementary particle with 1/2 integer spin such as electron
- Mikheyev-Smirnov-Wolfenstein effect: effect of matter on neutrino oscillation
- neutrino oscillation: neutrinos regularly morph into another flavor
- standard model: model of elementary particles including quarks
- TAMBO: concept for neutrino detector in valley in Peru
Tau Retrieval for Exoplanets (Tau-REx): spectral line retrieval code for exoplanet atmospheres
Tau-Aur Complex (Taurus-Auriga Complex): nearby star-forming region
Tau-REx: spectral line retrieval code for exoplanet atmospheres
Taub spacetime: early 1950s model for a rotating-black-hole spacetime
- Taub-NUT spacetime: early mathematics for a rotating black hole spacetime
Taub-NUT metric: see Taub-NUT spacetime
Taub-NUT spacetime: early mathematics for a rotating black hole spacetime
- Kerr-NUT spacetime: Kerr spacetime defined in terms of Taub-NUT spacetime
Tauras A (Crab Nebula): supernova remnant in Taurus
Taurus Auriga Perseus Complex: see Taurus-Auriga Complex
Taurus Dark Clouds (Taurus-Auriga Complex): nearby star-forming region
Taurus Molecular Cloud (Taurus Molecular Cloud 1): nearby star-forming region
- HL Tau: much-studied T-Tauri star
Taurus Molecular Cloud 1: nearby star-forming region
Taurus Molecular Cloud 2: see Taurus Molecular Cloud 1
Taurus Molecular Cloud 2: see Taurus-Auriga Complex
Taurus: balloon-borne polarimeter to study the CMB
TAURUS-1: see Isaac Newton Telescope
Taurus-Auriga Complex: nearby star-forming region
Taurus-Auriga Region (Taurus-Auriga Complex): nearby star-forming region
Taurus-Auriga SFR (Taurus-Auriga Complex): nearby star-forming region
Taurus-Auriga T association

T association: stellar association with T-Tauri stars

TAUVEX: see Spektr-RG
TAV: see rare designator prefixes
Taylor column: see Taylor-Proudman theorem
Taylor series

finite difference method: means of estimating calculus and differential equation solutions
Fourier transform: systematic method of breaking down functions into periodic components
Legendre polynomials: useful sequence of polynomials

Taylor series expansion

Bernstein polynomial: polynomial form capable of producing arbitrary shapes

Taylor-Proudman theorem: theorem regarding movement through a rotating fluid
TB: see CMB polarization
TBHD: see rare designator prefixes
TBJ: see rare designator prefixes
TBL

Zeeman-Doppler imaging: technique for imaging stellar magnetic fields

TBP (task-based parallelism): breaking a computation into tasks that can be run in parallel
TBTF: see dwarf galaxy problem
TC: see SELENE
Tc: see technetium star
Tc-rich star (technetium star): star showing technetium absorption lines
TCB: see time standard
TCG: see Terrestrial Time
TCP: see rare designator prefixes
TCS: see Teide Observatory
TD: see neutron star merger
- time standard: method of designating points in time and quantifying time periods
TD-1 (TD-1A): 1970s European observatory-satellite with UV telescopes
TD-1A: 1970s European observatory-satellite with UV telescopes
TD1: see TD-1A
TDB: see time standard
TDE (tidal disruption event): star pulled apart by black hole tidal forces
- AT2019dsg: 2019 TDE undergoing study
- optical transient: transient evident from visible light observation
TDF (tidal disruption event): star pulled apart by black hole tidal forces
TDRSS (Tracking and Data Relay Satellite System): NASA satellites used for communication and tracking of space probes
TDT

time standard: method of designating points in time and quantifying time periods

TDV: see transit timing variations
- exosatellite: natural satellite not in the solar system
TE (thermodynamic equilibrium): state of a system with no net heat flows
TE: see CMB polarization
technetium: see technetium star
technetium star: star showing technetium absorption lines
technique

2.5 dimensional model: model such as computer simulation between 2D and 3D
adaptive refinement tree: algorithm-type for solving n-body problem
aperture photometry: method of determining the brightness of an imaged star
apodization: improving telescope images by manipulating diffraction
Bernstein polynomial: polynomial form capable of producing arbitrary shapes
chemical tagging: using abundances to trace the origin of particular stars
cyclotron radiation emission spectroscopy: method of measuring the KE of beta particles
destriping: removing streak-like noise from images
drift scan: method of observing substantial sky with CCDs
dropout: means of identifying distant galaxies
Gini/M20: an automatable method of detecting whether a galaxy has recently merged
gravity assist: method of boosting the speed of a spacecraft
HARM²: technique for parallelizing computations of radiation with hydrodynamics
HCI: imaging of targets very near bright objects
Hough transform: algorithm used in image processing
Jeans anisotropic modeling: method of determining stellar kinematics of early type galaxies
line tomography: using double-peaked spectral lines to place constituents of a disk
Lock-In Amplified Externally Dispersed Interferometry: technique for precise RV measurement
machine learning: use of programs that extract their algorithms from data
Markov chain Monte Carlo: model technique to approximate multi-dimensional integrals
maximum likelihood estimation: statistical method to find likely parameters
maximum likelihood mapmaking: method of making maps using varying data
mixture density network: machine learning technique
neural network: computer program structure inspired by the brain
nondimensionalization: manipulation of an equation to remove units
numerical analysis: the study and use of numerical methods of solving equations
numerical methods: using equations through repetitive arithmetic
occultation observations: gathering astronomical information through measuring occultations
PCA analysis: an automatable method of determining galaxy morphology
photon counting: sensing EMR down to the photon level
PIC simulation: method used in simulating plasma
PSF fitting: untangling airy disks to gain effective resolution
quantum Monte Carlo: MC approach to difficult quantum mechanical problems
reverberation mapping: technique for measuring the size of SMBHs
shearing box: method of simulating 3D MHD in disks
sky subtraction: removing background radiation from a telescope observation
smoothed-particle hydrodynamics: computational method for simulating fluid flows
stellar population synthesis: using spectral characteristics of galaxies to characterize their stellar populations
subgrid-scale physics: shortcuts handling physics on a smaller scale than a simulation's grid
symbolic regression: automated model-building by tinkering with formulae
three dimensional model: computer simulation handling variation in all three dimensions
umbrella sampling: method usable in MCMC that avoids some problems
volume weighting: method of accommodating the Malmquist bias
Zanstra method: method of determining temperature of a hot star within a nebula
Zeeman-Doppler imaging: technique for imaging stellar magnetic fields

technology

American Institute of Aeronautics and Astronautics: society of engineers
duty cycle: percent of time when activity is recurring
Institute of Electrical and Electronics Engineers: professional engineering association
International Organization for Standardization: standards-development organization
laser com: laser communications
systematic error: errors with non-random characteristics

technomarker (technosignature): sign of technology
- biosignature: sign of life
technosignature: sign of technology
- biosignature: sign of life
TECP: see Phoenix
tectonic activity: see crustal plates
TEDI: see TripleSpec
Teegarden's Star: nearby red dwarf
Teff (effective temperature): temperature of an equivalent black body in terms of total radiation
TEGA: see Mars Polar Lander
TEGA: see Phoenix
Teide: see rare designator prefixes
Teide Observatory: observatory on Mount Teide in the Canary Islands
- Instituto de Astrofísica de Canarias: research institute on Canary Islands
- LSPE-STRIP: CMB survey telescope in Canary Islands
- SPECULOOS: search for Earth-like exoplanets orbiting nearby dim stars
- Tenerife Experiment: 1980s-1990s survey of CMB anisotropies
- Trans-Atlantic Exoplanet Survey: 2000s exoplanet-search survey using three telescopes
- Very Small Array: radio interferometer in Canary Islands
telegrapher's equations: two equations describing a transmission line
telescope: instrument to observe at a distance
- Africa Millimetre Telescope: planned 15 m radio telescope array in Namibia
- AGILE: Italian space gamma-ray observatory
- AKARI: Japanese space infrared telescope
- ALEXIS: 1990s soft X-ray transient monitor
- Algonquin Radio Observatory: 46 meter radio telescope
- Allen Telescope Array: array of radio telescopes in northern California for SETI
- Anglo-Australian Telescope: 3.9-m reflector telescope in Australia
- ARCADE: balloon-borne centimeter-wavelength surveyor
- Archeops: balloon-borne 1.3 m submillimeter telescope
- Arcminute Microkelvin Imager: pair of microwave arrays
- Arcus: X-ray space telescope plan aiming for 2031 launch
- Arecibo Observatory: former large 305 m radio telescope in Puerto Rico
- ARGO-YBJ Experiment: cosmic-ray/gamma-ray detector in Tibet
- Ariel 5: 1970s X-ray space telescope
- ARO 12m Telescope: twelve meter microwave telescope at KPNO
- ASCA: 1990s Japanese space X-ray telescope
- ASTHROS: balloon-borne 2.5-m submillimeter telescope
- Astronomical Netherlands Satellite: 1970s X-ray/ultraviolet space telescope
- Atacama B-Mode Search: 2012-2014 survey of the CMB
- Atacama Cosmology Telescope: 6-meter microwave survey telescope in Chile
- Atacama Large Millimeter Array: large millimeter telescope array in Chile
- Atacama Pathfinder Experiment: 12-meter submillimeter telescope in Chile
- Atacama Submillimeter Telescope Experiment: 10-meter submillimeter telescope in Chile
- ATHENA: planned ESA X-ray space telescope
- AtLAST: concept for submillimeter survey telescope in Chile
- Australia Telescope Compact Array: radio telescope in eastern Australia
- Australian Square Kilometre Array Pathfinder: radio telescope array of 36 12-meter dishes
- Automated Patrol Telescope: 0.5 m telescope at Siding Spring Observatory
- Automated Planet Finder: robotic telescope to find exoplanets using RV method
- AXIS: concept for space X-ray observatory
- BeppoSAX: Italian-Dutch space X-ray telescope
- BICEP2: survey to measure the polarization of the CMB
- BIMA telescope: millimeter interferometer in operation 1985 to 2005
- BINGO: future radio telescope for mapping distant neutral hydrogen
- Bisei Asteroid Tracking Telescope for Rapid Survey: Japanese telescope surveying to find NEOs and space junk
- BlackGEM: telescope array to follow up gravitational wave signals
- BLAST: balloon-borne 1.8-m submillimeter telescope
- BOOMERanG: 1990s-2000s balloon-borne 1.3-meter millimeter telescope
- Broad Band X-Ray Telescope: 1990s Astro-1 Space Shuttle X-ray telescope
- Burst and All Sky Imaging Survey: late 1990s GRB-observer satellite proposal
- BUSS: 1970s balloon-based ultraviolet astronomy mission
- California Extremely Large Telescope: concept for an extremely large telescope
- Caltech Submillimeter Observatory: 10.4 meter submillimeter telescope previously in Hawaii
- Canada-France-Hawaii Telescope: 3.6 meter optical/infrared telescope in Hawaii
- Canadian Hydrogen Intensity Mapping Experiment: radio telescope mapping distant neutral hydrogen
- CANGAROO: Collaboration between Australia and Nippon for a Gamma Ray Observatory in the Outback
- Carbon Monoxide Mapping Array: planned experiment to observe epoch of reionization
- CCAT: 25-meter submillimeter telescope plan for Chile
- Chandra X-ray Observatory: space X-ray telescope
- CHARA: optical interferometer on Mount Wilson
- CHEOPS: space telescope in development to measure radii of exoplanets
- Cherenkov Telescope Array: ground gamma-ray telescope array in development
- CHIPS: small satellite to investigate ISM plasma
- CIBER: sounding-rocket survey of near-infrared background
- CMB Stage-4: planned 2020s-generation of ground CMB observations
- COAST: optical interferometer in England
- Colossus Telescope: concept for a 50-meter telescope using interferometry
- COMAP: high frequency radio telescope to map CO
- Combined Array for Research in Millimeter-wave Astronomy: former array of radio telescopes in eastern California
- Compton Gamma Ray Observatory: 1990s space observatory for gamma ray observation
- Coronal Solar Magnetism Observatory: proposed solar observatory
- Cos-B: 1970s satellite for studying gamma rays
- COSI: 2000s balloon-based gamma ray telescope
- Cosmic Anisotropy Telescope: 1990s interferometer to measure CMB variations
- Cosmic Background Explorer: 1989 satellite for surveying the CMB
- Cosmic Background Imager: radio telescope in Chile observing the CMB
- Cosmic Dawn Intensity Mapper: NASA concept for space telescope for intensity mapping
- CubIXSS: solar spectrometer satellite concept
- CUTE: CubeSat ultraviolet space telescope
- DASI: 2000-2003 South Pole CMB telescope
- DKIST: 4 m solar telescope at Haleakala Observatory
- Dragonfly Telephoto Array: Canadian compact array of small visible-light telescopes
- DSA-2000: array plan to detect radio transients
- EBEX: balloon-based CMB polarization survey
- Effelsberg 100-m Radio Telescope: German large single-dish radio telescope
- Einstein Probe: Chinese X-ray space observatory
- eROSITA: Russian/German space X-ray telescope launched in 2019
- ESO 3.6m Telescope: reflector telescope at La Silla
- ESO Schmidt Telescope: 1 meter telescope in Chile with a wide field-of-view
- Euclid: survey observatory-satellite to measure dark energy
- European Extremely Large Telescope: 39-meter telescope under construction
- European Southern Observatory Very Large Telescope: four 8.2-meter optical telescopes in Chile that can act together
- Event Horizon Telescope: growing VLBI network
- EXCLAIM: planned balloon-borne 70-cm telescope with spectrometers
- EXOSAT: 1980s European space X-ray telescope
- eXTP: plan for a space X-ray telescope
- Extreme Ultraviolet Explorer: 1990s ultraviolet space telescope
- Far Ultraviolet Spectroscopic Explorer: early 2000s space telescope for short-wavelength ultraviolet
- FAST: Arecibo-like 500 m telescope in China
- Fast Fourier Transform Telescope: proposed all-digital telescope with synthetic aperture
- FAUST: 1990s ultraviolet space telescope used on two Space Shuttle missions
- Fermi: satellite for studying gamma rays
- Fred Young Submillimeter Telescope: 6-meter submillimeter survey telescope under construction in Chile
- Full-sky Astrometric Mapping Explorer: early 2000s proposal for an astrometric space telescope
- Gaia: astrometry survey satellite launched in 2013
- GaiaNIR: concept for a Gaia follow-on including NIR astrometry
- Galaxy Evolution Explorer: observatory-satellite with 50-cm ultraviolet telescope
- Galileo Observatory: 1960s-1970s infrared observatory aircraft
- Gattini-IR: IR transient survey telescope
- Giant Magellan Telescope: 24.5 meter telescope under construction
- Giant Metrewave Radio Telescope: large radio interferometer in India
- Giant Segmented Mirror Telescope: concept for an extremely large telescope
- Ginga: 1980s Japanese space X-ray telescope
- Glazar: 1980s UV space telescope on MIR space station
- Gran Telescopio Canarias: 10.4 meter telescope in the Canary Islands
- GRANAT: observatory-satellite for detecting gamma rays and X-rays
- GRAPES-3: Cherenkov telescope at Ooty, India
- Green Bank 140 Foot Telescope: West Virginia radio telescope
- Green Bank 300ft Telescope: former large radio telescope at Green Bank
- Green Bank Telescope: West Virginia large radio telescope
- Greenland Telescope: 12 m radio telescope in Greenland
- GUSTO: balloon-borne 0.9-m far-infrared telescope
- HabEx: proposed space mission to directly image exoplanets
- HALCA: Japanese space radio telescope operating 1997-2005
- Hale Telescope: 5.1 m reflector telescope in California
- HEAO-1: 1977 X-ray observatory space mission
- HEAO-2: 1978 X-ray observatory space mission
- HERA: low frequency radio telescope
- Herschel Space Observatory: infrared observatory-satellite with 3.5-meter reflector
- High Definition Space Telescope: proposed 12 m space telescope
- High Elevation Antarctic Terahertz Telescope: 61 cm FIR telescope in Antarctica
- High Energy Stereoscopic System: ground gamma-ray telescope array
- High Energy Transient Explorer: 2000s space multi-band GRB observatory
- High-altitude Water Cherenkov Observatory: New Mexico gamma ray telescope using Cherenkov radiation
- Hiltner Telescope: 2.4-meter reflector telescope at MDM observatory
- Hipparcos: ESA astrometry space observatory circa 1990
- HIRAX: radio telescope array for 21-cm surveying
- Hisaki: retired Japanese space ultraviolet telescope
- Hitomi: 2016 Japanese space X-ray telescope
- Hobby-Eberly Telescope: 10 meter telescope in Texas
- Hopkins Ultraviolet Telescope: 1990s ultraviolet space telescope used on two Shuttle Shuttle missions
- Hubble Space Telescope: observatory-satellite with 2.4-meter reflective telescope
- HXMT: space X-ray observatory launched in 2017
- Infrared Space Observatory: 1990s 60-cm infrared space telescope
- Infrared Survey Facility: 140 cm reflector telescope that images in infrared
- Infrared Telescope Maffei: 80 cm infrared telescope in Antarctica
- INTEGRAL: European gamma ray observatory-satellite
- International Liquid Mirror Telescope: 4-meter liquid mirror telescope under construction in India
- International Ultraviolet Explorer: 1980s ultraviolet space telescope
- Interplanetary Scintillation Array: UK radio telescope that first detected pulsars
- IOTA: past optical interferometer in Arizona
- IRAM 30m Telescope: millimeter-range radio telescope in Sierra Nevada, Spain
- IRAS: 1983 satellite that surveyed the sky in infrared
- IRTF: Mauna Kea 3-meter infrared telescope
- IRTS: 15-cm infrared telescope on Japanese satellite
- Isaac Newton Telescope: 2.5 m telescope in Canary Islands
- IXPE: space observatory with X-ray polarimeters
- James Clerk Maxwell Telescope: far-infrared telescope in Hawaii
- James Webb Space Telescope: 6.5-meter infrared space telescope at L2
- Japan Spaceguard Association: Japanese telescope tracking NEOs and space junk
- Joint European Telescope for X-ray astronomy: 1990s X-ray space observatory never launched
- K2: second Kepler mission that worked around failed equipment
- Keck Observatory: observatory in Hawaii with two 10-meter reflectors
- Kepler Telescope: space telescope that watched stars for exoplanets
- Kuiper Airborne Observatory: infrared observatory-plane in the 1980s
- LAMOST: Chinese telescope for spectroscopic surveys of stars and galaxies
- Large Altazimuth Telescope: 6-meter reflector telescope in Russia
- Large Binocular Telescope: dual 8.4 meter telescope in Arizona
- Large Earth-based Solar Telescope: 1990s plan for 2.4 m solar telescope
- Large Millimeter Telescope: large microwave telescope in Mexico
- Large Submillimeter Telescope: concept for a 50-meter submillimeter telescope in Chile
- Large Zenith Telescope: 6 meter liquid mirror telescope in British Columbia
- Livermore Optical Transient Imaging System: automated telescope aiming to catch GRB optical counterparts
- Liverpool Telescope: 2-meter robotic telescope in Spain
- Long Wavelength Array: radio telescope in New Mexico
- LOPES: cosmic ray detector that detected resulting radio
- Low-frequency Array: low frequency radio telescope
- Lowell Discovery Telescope: 4.3 m telescope at Lowell Observatory, Arizona
- LSPE-STRIP: CMB survey telescope in Canary Islands
- LSPE-SWIPE: plan for a balloon-based CMB polarization survey
- Lunar-based Ultraviolet Telescope: Chinese ultraviolet telescope on the Moon
- LUVOIR: plan for a space-based telescope
- Lynx: concept for space X-ray observatory
- Magellan Telescopes: pair of 6.5 m optical telescopes in Chile
- MAGIC: ground gamma-ray telescope array in the Canary Islands
- Mark II: 38 m radio telescope in England
- Maui Optical Tracking and Identification Facility: USAF optical/infrared telescopes to Earth-orbiting objects
- MAXIMA: 1998-1999 balloon-borne 1.3-meter millimeter telescope
- Mayall 4m Telescope: 4 meter reflector telescope at Kitt Peak
- Measuring Oscillations in Nearby Stars: past plan for asteroseismology mission
- MeerKAT: new radio telescope in South Africa
- MeerLICHT: South African telescope coordinated with MeerKAT
- Mercator Telescope: 1.2 m telescope in the Canary Islands
- MERLIN: VLBI array spread across England
- Midcourse Space Experiment: 1990s space telescope
- Milagro: gamma ray telescope using Cherenkov radiation
- MMT: 6.5 meter telescope at Mt. Hopkins, Arizona
- Mopra Telescope: Australian 22 m radio telescope
- MOST: radio telescope in New South Wales
- MRO Interferometer: optical interferometer in New Mexico
- Murchison Widefield Array: low frequency radio telescope
- Nançay Radio Telescope: large radio telescope in France
- NANTEN2: millimeter telescope in Chile
- Narrabri Stellar Intensity Interferometer: 1960s optical interferometer for measuring stellar diameters
- NASA Orbital Debris Observatory: 1990s telescope aimed at tracking space junk
- Navy Precision Optical Interferometer: optical interferometer in Arizona
- NEO Surveyor: planned space observatory to detect and monitor NEOs
- NEOSSat: small spacecraft tracking NEOs
- New Technology Telescope: 3.58-meter reflector telescope in Chile
- Next Generation Very Large Array: planned radio telescope array as a follow-on to ALMA and the Jansky VLA
- NICER: space X-ray mission specifically to view neutron stars
- Northern Extended Millimeter Array: large radio telescope array under construction in Europe
- NuSTAR: space telescope for high-energy X-rays
- Ooty Radio Telescope: cylindrical radio telescope in India
- Origins Space Telescope: concept for 2030s large space IR telescope
- Orion space telescopes: two Russian 1970s UV space telescopes
- OSO 7: 1970s observatory-satellite for viewing the Sun
- OSO 8: 1970s observatory-satellite for viewing the Sun
- Overwhelmingly Large Telescope: 100 m telescope plan
- OVRO-LWA: radio telescope in California
- Palomar 48 Inch Telescope: 48 inch Schmidt telescope at Palomar Observatory
- Palomar 60-inch Telescope: 60 inch telescope at Palomar Observatory
- Palomar Testbed Interferometer: near-infrared interferometer experiment
- Parkes Observatory: Australian observatory with large single-dish radio telescope
- Planck: microwave telescope in space
- Plateau de Bure Interferometer: 6-dish interferometer in French Alps
- PLATO: planned observatory-satellite aimed at finding exoplanets
- PRIMA: concept for 2030s NASA 1.8-m FIR space telescope
- QMAP: mid 1990s balloon-based CMB survey
- QUaD: survey to measure the polarization of the CMB
- QUBIC: survey measuring the polarization of the CMB
- QUIET: survey to measure the polarization of the CMB
- Rapid Eye Mount Telescope: quick-action robotic telescope at La Silla Observatory
- RATAN-600: ring-shaped radio telescope in Russia
- Roman Space Telescope: proposed near-infrared space observatory
- ROSAT: 1990s German space X-ray telescope
- Rubin Observatory: 8-meter survey reflector telescope under construction in Chile
- RXTE: space mission to time X-ray variations
- Sardinia Radio Telescope: Italian large single-dish radio telescope
- SCAP: 1980s balloon-borne ultraviolet telescope
- Shane Telescope: 3.05 m reflector telescope at Lick Observatory
- Simons Array: telescope array to map CMB polarization
- SkyMapper: automated 1.35 m optical telescope in Australia
- Sloan 2.5m Telescope: telescope for SDSS in New Mexico
- Small Astronomy Satellite 2: 1970s NASA gamma ray space telescope
- Small Astronomy Satellite 3: 1970s NASA X-ray space telescope
- SOAR Telescope: 4.1 m reflector telescope in Chile
- SOFIA: aircraft-based infrared observatory
- Solar and Heliospheric Observatory: satellite observing the Sun
- Solar Dynamics Observatory: 2010 satellite observing the Sun
- Solar Maximum Mission: 1980s satellite to study the Sun during solar maximum
- South Pole Telescope: a millimeter/microwave telescope at South Pole
- Southern African Large Telescope: 10-meter telescope in South Africa
- Southern Observatory for Near Earth Asteroids Research: private telescope tracking NEOs
- Space Surveillance Telescope: 3.5-m US telescope to discover and monitor objects in space
- Spektr-R: 10 m space radio telescope
- SPICA: plan for a future space IR telescope
- SPIDER: 2015 balloon-borne observatory to observe CMB polarization
- Spitzer Space Telescope: retired infrared space telescope
- Square Kilometre Array: planned radio telescope with square-kilometer collecting area
- STAR-X: plan for a future X-ray space telescope
- STARE: array of radio telescopes monitoring radio transients
- STROBE-X: space X-ray telescope plan
- STUDIO: balloon-borne 0.5 m ultraviolet telescope
- Subaru Telescope: 8.2 meter telescope in Hawaii
- Submillimeter Array: radio interferometer in Hawaii
- Submillimeter Telescope: 10-meter far-infrared telescope
- Submillimeter Wave Astronomy Satellite: submillimeter space telescope operating 1998-2004
- SUNRISE: balloon-borne 1 m solar telescope
- Sunyaev-Zel'dovich Array: array of eight 3.5 meter microwave telescopes
- SuperBIT: balloon-borne 0.5-m telescope
- SUSI: optical interferometer in Australia
- Suzaku: space X-ray telescope
- Swedish-ESO Submillimetre Telescope: 1990s 15 m submillimeter telescope in Chile
- Swedish-ESO Submillimetre Telescope: former 15 m radio telescope array in Chile
- Swift: satellite for studying gamma-ray bursts
- T4 Automated Photometric Telescope: automated 75-cm telescope to a long-term star monitoring survey
- Taurus: balloon-borne polarimeter to study the CMB
- Telescopio Nazionale Galileo: 3.58 m telescope in Canary Islands
- Tenerife Experiment: 1980s-1990s survey of CMB anisotropies
- Terrestrial Planet Finder: plan for space telescopes to find smaller exoplanets
- Thirty Meter Telescope: extremely large telescope planned for Hawaii
- Tianlai Project: 21-cm line intensity mapping project
- TIM: planned balloon-borne 2 m telescope and spectrometer
- Tokyo Photoelectric Meridian Circle: Japanese telescope to determine the position of stars and planets
- TopHat: 2001 balloon -based CMB survey
- TRACE: former solar observing satellite
- Transiting Exoplanet Survey Satellite: observatory-satellite searching for transiting exoplanets
- TRAPPIST: a ground-based automated transiting-planet finding telescope
- Uhuru: 1970 X-ray space telescope
- UK Schmidt Telescope: 1.2 meter telescope in Australia with wide field-of-view
- ULTRASAT: future satellite to detect UV transients
- Ultraviolet Imaging Telescope: 1990s ultraviolet space telescope used on two Space Shuttle missions
- United Kingdom Infrared Telescope: Mauna Kea 3.8 meter infrared telescope
- University of Tokyo Atacama Observatory: observatory for a 6.5 m infrared telescope under construction
- USNO Twin Astrograph: USNO astrograph deployed in 1970
- UTMOST: telescope aiming to detect radio transients
- Víctor M. Blanco Telescope: 4 meter reflector telescope in Chile
- VERA: VLBI project to map the Milky Way
- VERITAS: ground gamma ray telescope array in Arizona
- Very Large Array: radio telescope in New Mexico
- Very Small Array: radio interferometer in Canary Islands
- VISTA: 4.1 meter telescope in Paranal Observatory in Chile
- VLT Survey Telescope: survey telescope located at the VLT site
- Westerbork Synthesis Radio Telescope: radio telescope array of 14 dishes in Netherlands
- Wide Field Infrared Explorer: partly-failed 1999 infrared satellite
- Wide-field Infrared Survey Explorer: infrared space telescope aimed at an all-sky survey
- William Herschel Telescope: 4.2-meter telescope in the Canary Islands
- Wisconsin Ultraviolet Photo-polarimeter Experiment: 1990s ultraviolet space telescope used on two Shuttle Shuttle missions
- WIYN 3.5m Telescope: Kitt Peak telescope run by university collaboration and NOIRLab
- XMM-Newton: X-ray observatory-satellite operated by ESA
- XRISM: X-ray space telescope launched in 2023
- XTP: past plan for a space X-ray telescope
- Yohkoh: 1990s Japanese solar observatory spacecraft
- Yuan-Tseh Lee Array: microwave interferometer in Hawaii
Telescope Array Experiment (Telescope Array Project): cosmic-ray observatory aiming for extremely energetic particles
Telescope Array Low Energy extension: see Telescope Array Project
Telescope Array Project: cosmic-ray observatory aiming for extremely energetic particles
- Fly's Eye: 1980s cosmic-ray observatory
- High Resolution Fly's Eye: 1990s-2000s cosmic-ray observatory
Telescope Array RADAR: see Telescope Array Project
Telescope Nazionale Galileo

HARPS-N: high-precision spectrograph for exoplanet searches in Canary Islands

telescope nut: avid amateur telescope maker self-description
telescope operator: professional technical position at a research telescope site
telescope type: term indicating band or optics of a telescope
- astrograph: telescope designed for astrometry and other precise position measurements
- Astrolux: historically popular amateur telescope
- Cassegrain reflector: reflector telescope with convex secondary mirror
- Cherenkov detector: type of high energy photon or particle detector
- Compton telescope: type of gamma ray telescope for 0.75-30 MeV range
- coudé focus telescope: type of Nasmyth telescope with additional mirrors
- cylindrical telescope: telescope with cylindrical reflectors
- Dall-Kirkham telescope: type of reflector telescope
- Danjon astrolabe: instrument to measure the position of stars
- Dragone telescope: off-axis reflector telescope type that preserves polarization
- extremely large telescope: optical telescope with a 20+ meter aperture
- fiber-linked optical array telescope: scheme for a type of multi-mirror telescope
- Gregorian telescope: type of reflector telescope
- heliometer: instrument to precisely measure angles across the sky
- Herschelian telescope: type of off-axis reflector telescope
- Korsch telescope: type of three-mirror reflector telescope
- liquid mirror telescope: reflector telescope with primary mirror formed of spinning liquid
- meridian circle: instrument for timing the passage of stars over a meridian
- Nasmyth telescope: type of reflector telescope with secondary and tertiary mirrors
- Newtonian telescope: type of reflector telescope
- off-axis telescope: telescope
- pair telescope: telescope that detects gamma rays via pair production
- photographic zenith tube: telescope permanently mounted to the zenith
- prime focus: reflector telescope with no secondary mirror
- radio telescope: telescope that operates in the radio frequency range of EMR
- reflector telescope: telescope using mirrors rather than lenses to magnify
- refracting telescope: telescope using lenses rather than mirrors to magnify
- Ritchey-Chrétien telescope: type of two-mirror reflector telescope
- Schiefspiegler: type of off-axis reflector telescope
- Schmidt camera: telescope type with a very wide field of view
- Schmidt-Newton telescope: type of reflector telescope
- Schwarzschild telescope: type of two-mirror reflector telescope
- software telescope: telescope that depends more than normal upon software for analysis
- solar telescope: telescope designed to observe the Sun
- three-mirror anastigmat: general type of reflector telescope
- transit telescope: telescope able to shift aim up/down but not horizontally
- Wolter telescope: reflector telescope using only shallow-angle reflections
- Yolo telescope: type of reflector telescope
telescopes

1.3-mm observation: observation frequency useful for detecting dust
aberration: types of flaws in telescope images
ACe consortium: corporations contracted to construct E-ELT
actuator: telescope control motor
adaptive optics: optical mechanism to compensate for varying atmospheric distortion
airmass: measure of Earth-atmosphere attenuation for a telescope observation
Airy disk: image-pattern an optical system produces from light from a point
altazimuth mount: simple two-axis telescope mount
anastigmat: optics avoiding common aberrations
angular differential imaging: using telescope rotation to suppress speckles
angular magnification: a magnification measure for a magnifier with an eyepiece
angular resolution: measure of a telescope's ability to distinguish spatial detail
antenna pattern: a radio telescope's pattern of directional sensitivity
aperture: opening through which light passes
aperture masking interferometry: interferometry by means of a single telescope with a mask
apodization: improving telescope images by manipulating diffraction
aspheric mirror: mirror with other than a spherical curvature
astigmatism: focusing differently according to direction across the focal plane
astronomical observation request: term for a proposal to use a telescope
back end instrument: instruments of a telescope that process or combine signals
bandpass filter: device to filter away all but a band of frequencies
barrel distortion: distortion such that a square shows with convex edges
chopping mirror: internal pivoting mirror to slightly change the instrument's aim
chromatic aberration: focusing different wavelengths differently
collecting area: cross-sectional area over which a telescope receives EMR
commensal mode: telescope usage that accomplishes multiple observations simultaneously
confusion limit: limit on telescope imaging due to too many sources in the same region
continuous viewing zone: region of sky that can be viewed 7×24×365
coronagraph: telescope feature to block light from a specific body
deformable mirror: mirror that can be flexed for fine control
diffraction limited: telescope limited only by the laws of diffraction
diffraction spike: type of artifact in astronomical images of point sources
disperser: prism, grating, or grism within a spectrometer
distortion: aberration where the image is in focus but misshaped
drift scan: method of observing substantial sky with CCDs
elevation range: measure of how high and low a telescope can be pointed
emissivity: measure of a material's efficiency at radiating thermal radiation
equatorial mount: telescope mount with axis parallel to Earth's
etendue: measure of how wide and deep a telescope observes
Evryscope: automated array of telescopes to uncover transients
exit pupil: size of the image as presented to the eye
exposure time: time spent acquiring a signal
exposure time calculator: app to calculate time to carry out an observation
extreme adaptive optics: high-performance version of AO system
field curvature: focusing to a curved surface rather than a plane
field of view: angular measure of how much an optical instrument can view
filter: optical device to filter out part of the EMR spectrum
filter bank: set of filters to simultaneously produce radio data within bands
filter designator: indicators of a filter used in imaging
first light: initial demonstration that a telescope works
flux density: measure of the strength of a radio signal
focal length: length from optical element to focal plane
focal plane: plane within optical system at which an image is in focus
focal plane tilt: focal plane not perpendicular to the optical axis
fold mirror: flat mirror in a telescope to redirect the light
front end instrument: instruments of a telescope that detect and encode the signal
grating: spectrometer component
grazing incidence optics: optics that avoid large changes to the angle of rays
high-resolution imaging: typically, imaging with resolution better than a milliarcsecond
hot pixel: CCD pixel that shows more brightness than it should
illumination: measure of light energy producing a telescope's image
image stabilization: camera mechanism to compensate for movement
immersion grating: grating where light is within the material
integration time: time spent acquiring a signal
International Small Telescope Cooperative: former cooperative of small research telescopes
Isaac Newton Group of Telescopes: three telescopes in Canary Islands
legacy survey: phrase sometimes used in survey names
limiting magnitude: faintest magnitude that a telescope or instrument can detect
LPR: for "light pollution reduction"
lucky imaging: method of combining short-term images to yield better resolution
MASTER Robotic Net: network of automated telescopes to identify transients
mirror support cell: units in a telescope that support the mirror
monolithic mirror: telescope mirror made of one piece of material
National Astronomical Observatory of Japan: Japanese astronomy organization
National Optical Astronomy Observatory: previous name of US optical astronomy organization
National Radio Astronomy Observatory: US radio astronomy organization
natural astronomical telescopes: use of an astronomical body as a telescope
NOIRLab: US optical/infrared astronomy organization
null corrector: instrument for testing mirrors
observational astronomy: term covering observation
occulting bar: telescope feature to block light from a specific body
optical axis: center line through an optical instrument
optics: science and technology regarding visible light
Orbiting Astronomical Observatory: series of 1960s-1970s NASA space telescopes
Orbiting Wide-angle Light Collectors: space mission concept to detect cosmic rays through Earth atmosphere light flashes
outrigger: radio receiver some distance from main receiver for direction determination
phase plate: filter that changes the phase of light passing through
pincushion distortion: distortion such that a square shows with concave edges
plate scale: relation between angle and distance across an image
point source sensitivity: determination of how readily an instrument detects a point source
point-spread function: function describing an optical system's response to a point of light
pointed observation: observation of a specific target
pointing: the directing of a telescope at a point in the celestial sphere
pointing error: discrepancy in telescope's aim
primary mirror: main mirror in a reflector telescope
primary mission: the minimum operation expected of a scientific space mission
quad-ridge flared horn: type of horn that can be incorporated in radio telescope feeds
RAPTOR: automated array of telescopes to uncover and track transients
real image: image that would show on a screen placed at its location
reference star differential imaging: identifying speckles by comparing star-images
RoboNet: global network of robotic telescopes to follow up on GRBs
ROTSE: automated array of telescopes to uncover and track transients
scan speed: the speed at which the telescope changes angle on the sky while observing
seeing: apparent blurring and twinkling of objects seen through atmosphere
segmented mirror: a telescope mirror formed of an array of smaller mirrors
shift-and-add: common speckle-suppression technique
slew: rotating a telescope to point it
SPARTAN: series of astronomy satellites launched/retrieved by Space Shuttles
speckle imaging: method of combining short-term images to yield better resolution
speckle masking: speckle suppression technique using a calculation of the bispectrum
speckle suppression: methods of reducing noise in telescope observations
speckles: image flaws such as extraneous spots
spherical aberration: mis-focusing by spherically-curved mirrors and lenses
stacking: combining images of the same object
stray light: unintended light reaching a telescope's sensors
Strehl ratio: measure of optical aberration
systematic error: errors with non-random characteristics
TAROT: network of telescopes to catch GRB optical counterparts
telescope type: term indicating band or optics of a telescope
United States Space Surveillance Network: US survey-effort of space objects of interest
US ELT Program: NOIRlab program supporting the TMT and GMT
wavefront error: measure of a class of telescope distortion
wavefront sensor: instrument for determining a wave's deformation

Telescopes in Education: program giving grade-school students access to robotic telescopes
telescopic asterism: see asterism
Telescopio Carlos Sanchez: see Teide Observatory
Telescopio Nazionale Galileo: 3.58 m telescope in Canary Islands
- Roque de los Muchachos Observatory: observatory at La Palma in the Canary Islands
telluric (telluric star): star of known spectrum used for calibration
telluric contamination: see telluric line
- absorption line: dark line within a spectrum
- telluric star: star of known spectrum used for calibration
telluric correction: see telluric line
telluric line: absorption line in ground observation due to Earth atmosphere
- absorption line: dark line within a spectrum
telluric line subtraction: see telluric line
telluric planet (rocky planet): planet like Earth and Mars, mostly rock
telluric standard star (telluric star): star of known spectrum used for calibration
telluric star: star of known spectrum used for calibration
- telluric line: absorption line in ground observation due to Earth atmosphere
tellurium

CUORE: experiment to sense neutrinoless double beta decay

Tempel 1

Deep Impact: mission to create and observe an impact with a comet
EPOXI: mission using Deep Impact for further exploration
Stardust: space mission that collected and returned comet coma dust

temperature: measure of hotness/coldness of matter
- atmospheric temperature profile: the atmosphere's temperature by altitude
- brightness temperature: temperature of an equivalent black body in terms of spectral radiance
- color temperature: temperature-measure of a source based on a color index
- effective temperature: temperature of an equivalent black body in terms of total radiation
- electron volt: very small unit of energy
- equilibrium temperature: temperature a planet would have if it were an externally-heated black body
- greenhouse effect: mechanism that boosts temperature through selective blocking of EMR
- H-R diagram: diagram relating effective temperature to luminosity
- Hayashi limit: limit on the temperature of a star dependent upon its mass and luminosity
- Hess diagram: diagram relating effective temperature to luminosity
- kelvin: unit of temperature scale starting at absolute zero
- specific heat: ratio of added temperature to added heat for a material
- spectral temperature: temperature-measure of a source based on a spectrum
- stellar temperature determination: methods by which the temperature of a star is determined
- surface temperature: temperature of the surface of a star or planet
- turn-off point: point in H-R diagram of a cluster where stars turn red
- Wien's displacement law: relates temperature to wavelength of maximum emission
- Zanstra method: method of determining temperature of a hot star within a nebula
- zero-age main sequence: describes stars that just began hydrogen fusion
temperature gradient

stellar structure: the presumed internal structure of stars

temperature inversion: see atmospheric temperature profile
temperature profile (atmospheric temperature profile): the atmosphere's temperature by altitude
temperature scale height: see scale height
templates: mechanism to help classify many survey objects or events
Tempo

pulsar timing array: cooperating set of pulsar timing observatories

Tempo2

pulsar timing array: cooperating set of pulsar timing observatories

temps dynamique barycentrique: see time standard
temps-coordonnée barycentrique: see time standard
Tenagra observatory

Lick Observatory Supernova Search: search for supernovae for cosmological study

Tenerife

Teide Observatory: observatory on Mount Teide in the Canary Islands
Tenerife Experiment: 1980s-1990s survey of CMB anisotropies

Tenerife Experiment: 1980s-1990s survey of CMB anisotropies
TENGOO: see MMX
tensor

moment of inertia factor: characterization of mass distribution within a planet

TEP (Transits of Extrasolar Planets): late 1990s search for transiting planets
Teq (equilibrium temperature): temperature a planet would have if it were an externally-heated black body
terahertz

beat frequency: frequency emerging from two other frequencies

Terahertz Intensity Mapper (TIM): planned balloon-borne 2 m telescope and spectrometer
terminal-age main sequence: see zero-age main sequence
- post-main-sequence star: star evolved beyond its main sequence phase
termination shock: see heliosheath
terminator: line between regions of day and night
terminology

abiotic: produced by something other than life
basal: from the base or from below
celestial: having to do with stars and the sky
coalescence: merging together, becoming one thing
crowd-sourcing: carrying out large efforts by combining that of many volunteers
cryogenic: colder than 120 kelvins
dex: a number or ratio's log base 10
diagnostic: test or measurement that reveals something's characteristics
ejecta: material ejected from something
fusor: 2003 proposed term for astronomical objects capable of carrying out fusion
in situ: on site
inspiral: like an orbit that is growing smaller
microsatellite: NASA term for a 10-100 kg small satellite
morphology: form and structure
nanosatellite: NASA term for a 1-10 kg small satellite
small satellite: NASA term for a satellite of 1200 kg or less
smoking gun: convincing piece of evidence

Terra Hunting Experiment: search for exoplanets using HARPS3
terrestrial dynamical time

time standard: method of designating points in time and quantifying time periods

terrestrial gamma-ray flash: gamma rays emitted from Earth lightning storms
terrestrial planet (rocky planet): planet like Earth and Mars, mostly rock
Terrestrial Planet Finder: plan for space telescopes to find smaller exoplanets
Terrestrial Time: current measure of time for astronomical observations on Earth
terrestrial time: see time standard
tertiary mirror: see primary mirror
- astigmatism: focusing differently according to direction across the focal plane
- coudé focus telescope: type of Nasmyth telescope with additional mirrors
- Korsch telescope: type of three-mirror reflector telescope
- Nasmyth telescope: type of reflector telescope with secondary and tertiary mirrors
- three-mirror anastigmat: general type of reflector telescope
Terz: see rare designator prefixes
Terzan: see rare designator prefixes
TES (transition edge sensor): sensor using superconductivity's strong temperature sensitivity
TES: see Mars Global Surveyor
TES: see Mars Observer
- Cryogenic Dark Matter Search: a search for a candidate dark matter particle
- Cryogenic Rare Event Search with Superconducting Thermometers: a search for a candidate dark matter particle
TES bolometer: see transition edge sensor
TES Camera: see Atacama Submillimeter Telescope Experiment
TESCAM: see Atacama Submillimeter Telescope Experiment
tesla: unit of magnetic flux density
- gauss: measurement of magnetic field β
- magnetic flux density: vector field describing magnetism in relation to the Lorentz force
TESS (Transiting Exoplanet Survey Satellite): observatory-satellite searching for transiting exoplanets
- combined differential photometric precision: calculated relation of photometric variation to SNR
- ExoFOP: site to facilitate exoplanet follow-up observation
- LHS 3844 b: rocky planet in habitable zone of a red dwarf
- TESS-Keck Survey: Keck follow-up survey to TESS discoveries
- TOI 700 d: Earth-sized exoplanet in a habitable zone
TESS Duo: see Transiting Exoplanet Survey Satellite
TESS Follow-up Observing Program: see Transiting Exoplanet Survey Satellite
TESS input catalog: see Transiting Exoplanet Survey Satellite
TESS object of interest: see Transiting Exoplanet Survey Satellite
TESS-bis: see Transiting Exoplanet Survey Satellite
TESS-Keck Survey: Keck follow-up survey to TESS discoveries
Tethys: see Saturn
- moon: a planet's natural satellite, such as Earth's
tetrahedron

areal coordinate system: coordinate system based upon a known triangle

Teutsch: see rare designator prefixes
Texas

Hobby-Eberly Telescope: 10 meter telescope in Texas

Texas Interferometer: see Texas Survey of Radio Sources at 365 MHz
Texas Supernova Search: see supernova survey
Texas Survey of Radio Sources at 365 MHz: 1970s/1980s radio survey made with the Texas Interferometer
TEXES: see Gemini Observatory
texture: see topological defect
TFOP: see Transiting Exoplanet Survey Satellite
TFR (Tully-Fisher relation): relation between spiral galaxy luminosity and line width
TGE

gravimetry: measurement of gravity's strength

TGF (terrestrial gamma-ray flash): gamma rays emitted from Earth lightning storms
TGI: see QUIJOTE
TGO (Trace Gas Orbiter): ESA and Russian Mars orbiter-probe launched in 2016
TGSS: see Giant Metrewave Radio Telescope
TGU: see rare designator prefixes
Th: see rare designator prefixes
THA (Tucana Horologium association): nearby stellar association
THA: see rare designator prefixes
THA star: see Tucana Horologium association
THE (Terra Hunting Experiment): search for exoplanets using HARPS3
The Accident (WISE 1534-1043): nearby brown dwarf with high proper motion
The Amateur Sky Survey: amateur comet and variable-star search survey
The Anvil of Creation: see STARFORGE
The Arecibo Legacy Fast ALFA Survey (ALFALFA): HI survey of many galaxies
The B-Star Exoplanet Abundance Study (BEAST): survey of B stars for possible exoplanets
The Colossus Telescope (Colossus Telescope): concept for a 50-meter telescope using interferometry
The H2O Southern Galactic Plane Survey: survey of molecular clouds in the galactic plane
The LaSilla-QUEST Variability Survey

QUEST: sixteen square-degree survey camera

The Near Earth Space Surveillance Initiative: collaboration to survey NEOs
The PLUTO-Cloudy Interface: see Cloudy
The Survey for Ionization in Neutral Gas Galaxies: survey of HI in galaxies found through the H-alpha line
The Univese in Words (El Universo en palabras): Series of audios produced by Astroaccesible
Theano: see PyMC
Theia: see Moon formation
THEMIS: set of satellites studying the Earth's magnetic field
THEMIS: see Mars Odyssey
Themis

asteroid family: set of asteroids based on similar orbits

theoretical modified GR metric: metric devised to define modifications to GR
theory

axion: proposed light, electrically neutral elementary particle
black star: theoretical alternative to black holes
carbon planet: theoretical planet type with more carbon than oxygen
Chern-Simons gravity: one type of modified general relativity
common envelope: binary star system surrounded by a single gas cloud
core accretion model: model for the formation of giant planets
cosmic string: rent in spacetime
dark energy star: theoretical alternative to black holes
dark galaxy: gas and dark matter of a galaxy but with no stars
dark star: theoretical star-like object heated by dark-matter annihilation
DGP gravity: alternative theory of gravity addressing "dark energy"
electron capture supernova: supernova from collapse of iron-free stellar cores
entropic gravity: MOND-like theory of gravity
exotic star: term for theoretical stars not made of atoms/ions
fuzzball: theoretical alternative to black holes based on superstring theory
galaxy formation: modeled as collapsing clouds
Geroch-Bekenstein engine: hypothetical engine to overcome thermodynamics laws using a black hole
grand tack hypothesis: solar system formation model with Jupiter and Saturn migrating
gravistar: theoretical type of black hole with certain contents
gravitational instability model: model for the formation of giant planets
graviton: quantum of gravity
Hanbury Brown and Twiss effect: EMR interference stemming from variation in intensity
Hartle-Thorne metric: metric approximating GR effects of slow neutron star rotation
helium planet: gas giant with helium atmosphere
Hills Cloud: cloud of comets and minor planets around the solar system
hypercompact stellar system: SMBH with no galaxy but has a tight stellar cluster
hyperon: exotic type of baryon
Johannsen-Psaltis metric: metric template allowing metrics to be written as a general expansion
Kerr-NUT spacetime: Kerr spacetime defined in terms of Taub-NUT spacetime
liquid planet: planet consisting of liquid
Mach's principle: the notion that rotation is relative to all the mass of the universe
Magnetospheric eternally collapsing object: theoretical state of collapsing object unable to reach BH characteristics
Majorana particle: theoretical particle that is its own antiparticle
Milkomeda: future galaxy resulting from merger of Milky Way and Andromeda
mixing length theory: tractable simplified model of convection
modified Newtonian dynamics: alternative theory to "dark matter"
neutralino: proposed type of particle that might include WIMPs
oligarch: term for large planetesimals that dominate
pair-instability supernova: type of large supernova
Planet Nine: theoretical planet beyond Neptune
Population III: stars with no metallicity
primordial black hole: black holes forming at the most dense volumes when inflation ceased
Randall-Sundrum model: particular 5-dimensional cosmological model
silicate weathering feedback: feedback mechanism stabilizing carbon in Earth atmosphere
SMBH formation: process by which SMBHs form
Soltan argument: distant quasars imply SMBHs still exist
spinning dust emission: source of microwave signal
standard model of a flare: description of how solar flares function
string theory: type of physics theory bringing together current models
supergravity: combination of general relativity and supersymmetry
supersymmetry: extension to standard model of particle physics
Taub spacetime: early 1950s model for a rotating-black-hole spacetime
Taub-NUT spacetime: early mathematics for a rotating black hole spacetime
theoretical modified GR metric: metric devised to define modifications to GR
Thorne-Żytkow object: giant star with a neutron star at its center
vulcanoid: theoretical asteroid orbiting within Mercury's orbit
water-ice planet: planet made entirely of water ice
wormhole: connection between two regions in a curved space

theory of equilibrium figures (theory of figures): type of model relating a planet's shape to its rotation
Theory of Everything: single law explaining the four forces of nature
- symmetry breaking: loss of symmetry, such as due to loss of stability in a regime change
theory of figures: type of model relating a planet's shape to its rotation
theory of figures of planets rotating in hydrostatic equilibrium (theory of figures): type of model relating a planet's shape to its rotation
thermal bremsstrahlung: type of EMR produced by thin, hot plasma
- thermal emission: EMR due to a body's heat
thermal broadening (Doppler broadening): broadening of spectral lines due to movement of the sources of photons
- line shape function: function describing the shape of a spectral line
thermal diffusivity

Rayleigh number: measure reflecting a fluid system's propensity to convection

thermal Doppler broadening (Doppler broadening): broadening of spectral lines due to movement of the sources of photons
- line shape function: function describing the shape of a spectral line
thermal dust emission: glow of dust heated by stars or AGNs
thermal emission: EMR due to a body's heat
- black-body radiation: EMR with a characteristic spectrum due to the temperature of a body
- continuum emission: continuous spectrum such as black-body radiation or bremsstrahlung
thermal energy: see kinetic energy
thermal equilibrium: state of a system with no net heat flows
thermal escape: see atmospheric escape
- hydrodynamic escape: escape of gas particles from atmosphere due to heating
- Jeans escape: type of ongoing escape of gas particles from atmosphere
- Jeans parameter: ratio measuring a tendency of an atmosphere to escape
thermal inertia: a measure of a material's ability to absorb heat through conduction
thermal infrared: infrared emission due to black body radiation
thermal inversion: see atmospheric temperature profile
thermal IR: see infrared
thermal KID: see KID
thermal noise: noise inherent in electronic component warmer than absolute zero
- photon noise: variation in light measurement due to its quantum nature
thermal phase curve: see phase curve
thermal pulse: pulse in an AGB star due to helium fusion in a shell
- helium flash: helium ignition in a star
- helium runaway: helium fusion positive feedback through its generated heat
thermal pulse AGB: see asymptotic giant branch
thermal pulse cycle: see thermal pulse
thermal radiation (thermal emission): EMR due to a body's heat
- black-body radiation: EMR with a characteristic spectrum due to the temperature of a body
- emissivity: measure of a material's efficiency at radiating thermal radiation
thermal runaway: situation where heat triggers more heat production
- helium flash: helium ignition in a star
- helium runaway: helium fusion positive feedback through its generated heat
- thermal pulse: pulse in an AGB star due to helium fusion in a shell
thermal Sunyaev-Zel'dovich effect: see Sunyaev-Zel'dovich effect
thermal tide: see atmospheric tide
thermal timescale (Kelvin-Helmholtz timescale): time that would radiate away a body's heat energy given its luminosity
thermal timescale: see timescale
thermal Urca process: see Urca process
thermal wind: type of wind due to temperature gradients that vary by altitude
thermal wind balance: see thermal wind
thermodynamic equilibrium: state of a system with no net heat flows
- thermal equilibrium: state of a system with no net heat flows
thermodynamics: physics of heat and energy
- adiabatic process: process that occurs with no transfer of heat
- black hole thermodynamics: science of black holes
- entropy: relative measure of the amount of usable energy available
- heating: increasing the velocity of particles
- ideal gas law: relates pressure, temperature, and volume
- local thermodynamic equilibrium: state when temperature variation is too small to matter
- mechanics: the science of forces and motions
- phase transition: transformation from one state of matter to another
- specific heat: ratio of added temperature to added heat for a material
- thermal inertia: a measure of a material's ability to absorb heat through conduction
thermoelectric effect: see MMRTG
thermonuclear supernova (Type Ia supernova): type of supernova for which distance can be determined
- supernova: stellar explosion larger than a nova
thermosphere: see atmospheric temperature profile
- ionosphere: layers of Earth atmosphere with significant ions
Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED): space probe observing Earth upper atmosphere for solar effects
THESEUS: plan for X-ray/Gamma-ray transient space mission
Theta 1 Orionis (Trapezium Cluster): open cluster of stars in Orion Nebula
Theta¹ Orionis (Trapezium Cluster): open cluster of stars in Orion Nebula
thick disk: disk-shaped set of older stars within the Milky Way
thick disk: see disk galaxy
- advection dominated accretion flow: accretion without radiating much energy
- alpha-enhanced: metallicity with a high percentage of alpha elements
- galactic disk: the "disk" portion of a disk galaxy
- Milky Way: our galaxy
- thin disk: disk-shaped set of younger stars within the Milky Way
thick disk stars: see disk galaxy
thick shell: see Europa
thin disk: disk-shaped set of younger stars within the Milky Way
thin disk (alpha disk): well-known model of an accretion disk
thin disk: see disk galaxy
- AGN accretion: an SMBH's accretion, such as powers AGNs/quasars
- alpha-enhanced: metallicity with a high percentage of alpha elements
- galactic disk: the "disk" portion of a disk galaxy
- Milky Way: our galaxy
- thick disk: disk-shaped set of older stars within the Milky Way
thin disk accretion: see alpha disk
thin disk stars: see disk galaxy
thin shell: see Europa
Third Cambridge Catalogue of Radio Sources: 1959 catalog of northern hemisphere 159-MHz sources
Third Catalogue of Nearby Stars (Gliese-Jahreiss Catalog): 1991 catalog of stars within 25 parsecs
third dredge-up: see dredge-up
Third Reference Catalogue of Bright Galaxies: see Reference Catalogue of Bright Galaxies
third-order coma

Ritchey-Chrétien telescope: type of two-mirror reflector telescope

third-order TOF: see theory of figures
Thirty Meter Telescope: extremely large telescope planned for Hawaii
Thomson optical depth: a measure of effects of Thomson scattering
Thomson scattering: elastic scattering of photons by a charged particle
- electron scattering: any process that changes the course of an electron
- Klein-Nishina formula: formula for the effects of electrons scattering photons
Thomson scattering optical depth (Thomson optical depth): a measure of effects of Thomson scattering
Thomson thick: see Thomson optical depth
THOR: see ADAM::THOR
Thor-Delta 1A (TD-1A): 1970s European observatory-satellite with UV telescopes
thorium

Earth: third solar system planet from the Sun
potassium/thorium ratio: indication of thermal history

Thorne-Żytkow object: giant star with a neutron star at its center
Thousand Astronomical Units: 1980s plan for space probe to travel 1000 AU over 50 years
three dimensional model: computer simulation handling variation in all three dimensions
- subgrid-scale physics: shortcuts handling physics on a smaller scale than a simulation's grid
three mirror anastigmat

anastigmat: optics avoiding common aberrations

three-body capture: see tidal capture
three-body problem: see N-body problem
- Jacobi integral: method of solving some three-body problems
three-mirror anastigmat: general type of reflector telescope
Thuan-Gunn photometric system (griz photometric system): photometric system designed for electronic sensors
Ti (titanium): metal, Ti, atomic number 22
Tiangong space station: Chinese manned space laboratory under construction in space
Tianlai (Tianlai Project): 21-cm line intensity mapping project
Tianlai Cylinder Array: see Tianlai Project
Tianlai Dish Array: see Tianlai Project
Tianlai Experiment (Tianlai Project): 21-cm line intensity mapping project
Tianlai Project: 21-cm line intensity mapping project
TianQin: proposed Chinese space mission to detect gravitational waves
Tianwen-1: active Chinese Mars rover/orbiter mission
Tianyan (FAST): Arecibo-like 500 m telescope in China
Tibet

ARGO-YBJ Experiment: cosmic-ray/gamma-ray detector in Tibet

TIC: see Hipparcos
TIC: see Transiting Exoplanet Survey Satellite
TICCE: see EURECA
tidal

galactic tide: effect of one galaxy's gravity, such as on another galaxy
Love number: measures of rigidity of a body
Roche limit: nearest a body can orbit another and survive
tidal arm: arm of gas and potentially stars leading from a galaxy
tidal disruption event: star pulled apart by black hole tidal forces
tidal force: effect of a third body on the gravitational force between two bodies
tidal heating: heating due to friction from motions caused by tidal force
tidal locking: locked rotation of an orbiting body
tidal migration: interaction between tide and orbiting body that changes the orbit
tidal Q: measure of orbital energy dissipated per orbit due to tidal forces
tidal tail: string of mass ejected by a tidal forces in a neutron star merger

tidal acceleration: see tidal force
- tidal migration: interaction between tide and orbiting body that changes the orbit
tidal arm: arm of gas and potentially stars leading from a galaxy
- stellar stream: long group of co-moving stars
tidal braking: see tidal force
tidal capture: bodies entering orbit through dissipation of energy by tides
tidal deceleration: see tidal force
tidal deformability: see neutron star merger
tidal deformability parameter: see neutron star merger
tidal disruption event: star pulled apart by black hole tidal forces
- AT2019dsg: 2019 TDE undergoing study
- optical transient: transient evident from visible light observation
tidal disruption flare (tidal disruption event): star pulled apart by black hole tidal forces
tidal disruption radius: see Hill radius
tidal dissipation function: see tidal Q
tidal equilibrium: see tidal force
tidal flexing (tidal heating): heating due to friction from motions caused by tidal force
tidal force: effect of a third body on the gravitational force between two bodies
tidal heating: heating due to friction from motions caused by tidal force
- inflated radii: exceptionally large radii of some hot Jupiters
tidal locking: locked rotation of an orbiting body
tidal migration: interaction between tide and orbiting body that changes the orbit
tidal parameter: see neutron star merger
tidal period: see tidal Q
tidal plume: see tidal tail
tidal potential: see tide
tidal Q: measure of orbital energy dissipated per orbit due to tidal forces
tidal Q factor (tidal Q): measure of orbital energy dissipated per orbit due to tidal forces
tidal Q factor: see Q factor
tidal quality factor (tidal Q): measure of orbital energy dissipated per orbit due to tidal forces
tidal quality factor: see Q factor
tidal radius (Hill radius): radius of gravitational influence of a body
tidal shell: see shell galaxy
tidal stream: see stellar stream
- tidal arm: arm of gas and potentially stars leading from a galaxy
tidal stripping: see tidal arm
tidal tail: string of mass ejected by a tidal forces in a neutron star merger
tidal tail (tidal arm): arm of gas and potentially stars leading from a galaxy
- galaxy interaction: the effects of galaxies being near each other
- shell galaxy: galaxy with one or more surrounding layers of brightness
tidal theory

nebular hypothesis: model positing solar system planets result from a solar disk

tidal working (tidal heating): heating due to friction from motions caused by tidal force
tidal-capture binary: see binary star
tidal-capture binary: see tidal capture
tidal-tail galaxy: see tidal arm
tidally excited oscillation: see tidal migration
tide: effect of Moon's gravity on Earth's seas, etc.
- atmospheric tide: tide-type movement within the atmosphere
TIDI: see TIMED
TIE (Telescopes in Education): program giving grade-school students access to robotic telescopes
TIFKAM: see Hiltner Telescope
TIFR (Tata Institute of Fundamental Research - India): Indian math and science research institute
TIFR GMRT Sky Survey: see Giant Metrewave Radio Telescope
tiger stripes: see Enceladus
Tillinghast: see Fred Lawrence Whipple Observatory
- CfA Redshift Survey: 1970s-1990s surveys of galaxy redshifts
Tillotson EoS (Tillotson equation): equation of state for high speed impacts
Tillotson equation: equation of state for high speed impacts
Tillotson equation of state (Tillotson equation): equation of state for high speed impacts
tilt (obliquity): angle between an object's rotational and orbital axes
tilt erosion: see obliquity
TIM: planned balloon-borne 2 m telescope and spectrometer
TIME (Tomographic Ionized-carbon Mapping Experiment): instrument in development to map the [CII] line
time

BJD: barycentric Julian day
cosmic time: time since the Big Bang
epoch: when an object was at a particular set of celestial coordinates
epoch B1950.0: midnight 1/1/1950 GMT as used as a time reference
epoch J2000.0: noon 1/1/2000 GMT as used as a time reference
equinox: point-in-time when tilt of Earth is neither toward nor away from the Sun
gigayear: a billion years
Hubble time: approximation of the age of the universe
Julian calendar: calendar of 365 days and a leap day once every four years
Julian date: time in days since noon UT November 24 4714 BC Gregorian
local noon: time at a locality when the Sun is at its highest
local sidereal time: same as angular hours right ascension of the zenith
sidereal: relative to the fixed position of the stars
solar day: length of a solar system planet or Moon's day
solar time: time based upon the position of the Sun in the Earth's sky
Terrestrial Time: current measure of time for astronomical observations on Earth
time standard: method of designating points in time and quantifying time periods
timescale: general length of time something takes

time dilation: relativity's ability to make time differ for different objects
- cosmological time dilation: very distant events appear to take longer
time domain astronomy

transient: observed change in the sky
transient astronomy: study of short-term astronomical phenomena

Time History of Events and Macroscale Interactions during Substorms (THEMIS): set of satellites studying the Earth's magnetic field
time scale (time standard): method of designating points in time and quantifying time periods
time scale (timescale): general length of time something takes
time series

lightkurve: software to analyze time series data

time series analysis: analysis of data points collected at uniformly-separated times
- data folding: locating periods in data by trial
- fast folding algorithm: algorithm to find the periods of periodic data
- Period04: software to identify periods in time series data
- phase dispersion minimization: particular method of finding periodic components in signal
time series data

fast folding algorithm: algorithm to find the periods of periodic data

time standard: method of designating points in time and quantifying time periods
time system (time standard): method of designating points in time and quantifying time periods
time zone

solar time: time based upon the position of the Sun in the Earth's sky

time-delay cosmology: working out space geometry from delays due to gravitational lensing
time-domain astronomy: observing and analyzing changes in astronomical objects
TIME-EXT: see Tomographic Ionized-carbon Mapping Experiment
time-like: see spacetime diagram
- geodesic: equivalent to a straight line within curved space
TIME-NG: see Tomographic Ionized-carbon Mapping Experiment
time-of-flight spectrometer: see particle spectrometer
time-ordered data: observation data arranged by the time it was received
TIME-pilot: see Tomographic Ionized-carbon Mapping Experiment
TIMED: space probe observing Earth upper atmosphere for solar effects
timescale: general length of time something takes
- free-fall time: time it would take a body to collapse if unopposed
- Kelvin-Helmholtz timescale: time that would radiate away a body's heat energy given its luminosity
- Lyapunov time: timescale beyond which a dynamical system is chaotic
- Salpeter timescale: timescale for black hole growth
timestream: stream of digital data representing measurements taken over time
timing

Chinese Pulsar Timing Array: group of pulsars timed by FAST
European Pulsar Timing Array: European collaboration of radio telescopes
GUPPI: radio-telescope back-end aimed at processing pulsar data
Indian Pulsar Timing Array: group of pulsars timed by the GMRT
International Pulsar Timing Array: organization of pulsar timing arrays
MeerKAT Pulsar Timing Array: group of pulsars timed by MeerKAT
NANOGrav: effort to detect gravitational waves through pulsar timing
Parkes Pulsar Timing Array: group of pulsars timed by Parkes Observatory
pulsar timing array: cooperating set of pulsar timing observatories
PUPPI: Arecibo radio-telescope instrument aimed at observing pulsars

timing noise: see pulsar timing array
TIMMI-2: see ESO 3.6m Telescope
TIMMI2: see New Technology Telescope
Tinsley-Wallerstein diagram ([α/Fe] versus [Fe/H] diagram): diagram indicating stars' degree of alpha enhancement
TiNy Titans: study of dwarf galaxy pairs
TiO: see titanium
tip of the red-giant branch: standard candle consisting of the brightest RGB stars
TIR (thermal infrared): infrared emission due to black body radiation
TIR (total infrared): typically meaning a wide wavelength range covering NIR to FIR
TIR: see Hayabusa2
tired light: an alternate theory explaining the cosmological redshift
Titan: well-known Saturn moon
- Cassini: explorer spacecraft sent to Saturn
- Dragonfly: Titan flying rover under development
- moon: a planet's natural satellite, such as Earth's
- Saturn: second largest planet in the solar system
Titan Atmospheric Model (TAM): non-gray-RT 3D model of Titan's atmosphere
Titania: see Uranus
- moon: a planet's natural satellite, such as Earth's
titanium: metal, Ti, atomic number 22
titanium monoxide: see titanium
titanium-44: see titanium
Titius-Bode law: relationship between the distances between solar system planets
Titius-Bode rule (Titius-Bode law): relationship between the distances between solar system planets
titrant: see titration
titration: analyzing a chemical solution by color change
titrimetry (titration): analyzing a chemical solution by color change
TJ: see rare designator prefixes
tKID: see KID
TKS (TESS-Keck Survey): Keck follow-up survey to TESS discoveries
TLE (two-line element set): data format to record the position and motion of a satellite
TLF (tremendously low frequency): presumably electromagnetic radiation, frequency below 3 Hz
TLM: magnitude of the dimmest astronomical object you can see
TLP (lunar transient phenomenon): observed transient on the Moon such as a flash of light
TMC (Taurus Molecular Cloud 1): nearby star-forming region
TMC-1 (Taurus Molecular Cloud 1): nearby star-forming region
TMC-2: see Taurus Molecular Cloud 1
TMC-2: see Taurus-Auriga Complex
TMO (Table Mountain Observatory): NASA observatory near Los Angeles
TMSS (Two Micron Sky Survey): 1969 infrared catalog produced by Caltech
TMT (Thirty Meter Telescope): extremely large telescope planned for Hawaii
- extremely large telescope: optical telescope with a 20+ meter aperture
- Mauna Kea: Hawaiian mountain, the site of observatories
- Mauna Kea Observatories: observatories on Mauna Kea in Hawaii
Tmz: see rare designator prefixes
TN (telescope nut): avid amateur telescope maker self-description
TN: see USS Sources
TN: see pulsar timing array
TNG (Telescopio Nazionale Galileo): 3.58 m telescope in Canary Islands
- Roque de los Muchachos Observatory: observatory at La Palma in the Canary Islands
TNO (trans-Neptune object): minor planet beyond Neptune
- Haumea: dwarf planet discovered in 2004
- Pluto: dwarf planet formerly listed as one of the nine planets
- Sedna: distant solar system planetoid discovered in 2003
TNOs

solar system object: the Sun, solar system planets, minor planets, comets, and moons

TNS (Transient Name Server): online catalog of transients
- fast radio burst: astronomical high energy radio pulses of a few milliseconds
- supernova designator: typical designation of supernovae
TNT (TiNy Titans): study of dwarf galaxy pairs
TO (telescope operator): professional technical position at a research telescope site
TO (turn-off point): point in H-R diagram of a cluster where stars turn red
TOA: time of arrival
TOD (time-ordered data): observation data arranged by the time it was received
TOE (Theory of Everything): single law explaining the four forces of nature
- symmetry breaking: loss of symmetry, such as due to loss of stability in a regime change
TOF (theory of figures): type of model relating a planet's shape to its rotation
TOI: see Transiting Exoplanet Survey Satellite
- ExoFOP: site to facilitate exoplanet follow-up observation
TOI 700: see TOI 700 d
TOI 700 d: Earth-sized exoplanet in a habitable zone
Tokyo Atacama Observatory (University of Tokyo Atacama Observatory): observatory for a 6.5 m infrared telescope under construction
Tokyo Photoelectric Meridian Circle: Japanese telescope to determine the position of stars and planets
Tokyo Photoelectric Meridian Circle Catalog: see Tokyo Photoelectric Meridian Circle
Tokyo PMC Catalog: see Tokyo Photoelectric Meridian Circle
Tol: see Cerro Tololo Inter-American Observatory
Tolman VII object: theoretical object adhering to exact GR solution
Tolman VII solution: see Tolman VII object
Tolman-Oppenheimer-Volkoff equation: see Tolman-Oppenheimer-Volkoff limit
Tolman-Oppenheimer-Volkoff limit: maximum mass of a neutron star
Tololo: see Cerro Tololo Inter-American Observatory
TolTEC: sensitive infrared camera under construction for the LMT
TolTEC: see Large Millimeter Telescope
TolTEC C2C: see TolTEC
TolTEC FiF: see TolTEC
TolTEC LSS: see TolTEC
TolTEC UD: see TolTEC
Tombaugh: see rare designator prefixes
Tomographic Ionized-carbon Mapping Experiment: instrument in development to map the [CII] line
tomographic magnetic imaging (Zeeman-Doppler imaging): technique for imaging stellar magnetic fields
tomography: observation of sections of a 3D object
- Zeeman-Doppler imaging: technique for imaging stellar magnetic fields
Ton (Tonantzintla Surveys): surveys providing early images of quasars and Seyfert galaxies
Tonantzintla: see Tonantzintla Surveys
Tonantzintla Observatory

Tonantzintla Surveys: surveys providing early images of quasars and Seyfert galaxies

Tonantzintla Surveys: surveys providing early images of quasars and Seyfert galaxies
ToO: target of opportunity
too-big-to-fail problem: see dwarf galaxy problem
Toomre Q parameter: stability criterion for differentially rotating disks
Toomre sequence: model relating galaxy mergers to observation
Toomre's stability criteria: see Toomre Q parameter
top: see flavor
top down model: see galaxy formation
top hat filter: type of image processing mechanism to make small objects stand out
top quark: see particle
top quark: see quark
- standard model: model of elementary particles including quarks
TopHat: 2001 balloon -based CMB survey
topological defect: defect in space that could arise in the early universe
- cosmic string: rent in spacetime
TOPS (Toward Other Planetary Systems): workshops on developing techniques and observing programs
toroidal: see torus coordinates
torr: unit of pressure approximating a millimeter of mercury on Earth
tortuosity: describes something curved with many twists and turns
torus

torus coordinates: coordinates for toruses

torus coordinates: coordinates for toruses
total derivative: see partial differential equation
total differential equation: see partial differential equation
total duration: see transiting planet
total energy: see relativistic energy
total infrared: typically meaning a wide wavelength range covering NIR to FIR
total infrared luminosity: luminosity over a wide IR range
total mass

binary star: system of two stars co-orbiting

total precipitable water: see precipitable water vapor
total relativistic energy: see relativistic energy
total solar eclipse: see solar eclipse
TOURNESOL: see GRANAT
TOV (Tolman-Oppenheimer-Volkoff limit): maximum mass of a neutron star
TOV equation: see Tolman-Oppenheimer-Volkoff limit
Toward Other Planetary Systems: workshops on developing techniques and observing programs
tower: see solar telescope
TP (thermal pulse): pulse in an AGB star due to helium fusion in a shell
TP-AGB: see asymptotic giant branch
- thermal pulse: pulse in an AGB star due to helium fusion in a shell
TPC: see thermal pulse
TPCI: see Cloudy
TPF (Terrestrial Planet Finder): plan for space telescopes to find smaller exoplanets
TPW: see precipitable water vapor
TR: see OGLE
TRACE: former solar observing satellite
Trace Gas Orbiter: ESA and Russian Mars orbiter-probe launched in 2016
tracer: chemical whose detection indicates the presence of something else
Tracking and Data Relay Satellite System: NASA satellites used for communication and tracking of space probes
Tracklet-less Heliocentric Orbit Recovery: see ADAM::THOR
trade winds

Hadley cell: circulation pattern of up at the equator, poleward, down, and back
intertropical convergence zone: circulation pattern near equator where north and south Hadley cells meet
zonal flow: east-west air circulation

traditional approximation of rotation: approximation of waves on a rotating body
training

convolutional neural network: type of image processing software

Trans-Atlantic Exoplanet Survey: 2000s exoplanet-search survey using three telescopes
trans-iron element: elements with atomic number greater than that of iron
trans-Neptune binary: see binary minor planet
- trans-Neptune object: minor planet beyond Neptune
trans-Neptune object: minor planet beyond Neptune
trans-Neptune objects

minor planet: lesser solar system body without comet characteristics
solar system object: the Sun, solar system planets, minor planets, comets, and moons

trans-Neptunian object (trans-Neptune object): minor planet beyond Neptune
transfer equation (equation of radiative transfer): equation describing energy transfer by EMR
transformation group

Lie transform: type of infinitesimal transform

transient: observed change in the sky
- AT2018cow: unusual 2018 optical transient
- AT2019dsg: 2019 TDE undergoing study
- FRB121102: first repeating FRB discovered
- GW170817: 2017 gravitational wave detection from a neutron star merger
- Kepler's Supernova: Type Ia supernova observed in 1604 by Johannes Kepler
- lunar transient phenomenon: observed transient on the Moon such as a flash of light
- Oh-My-God Particle: extremely energetic particle from space detected in 1991
- SN 1572: Type Ia supernova noted in 1572 by Tycho Brahe
- SN 185: supernova recorded in China in AD 185
- SN 1987A: supernova in February 1987 rare for being visible by the naked eye
- SN 2014J: Type Ia supernova in Messier 82, the Cigar Galaxy
- stellar merger: two stars combining into one
transient astronomical event (transient): observed change in the sky
transient astronomical event: see transient astronomy
transient astronomy: study of short-term astronomical phenomena
- optical transient: transient evident from visible light observation
- time-domain astronomy: observing and analyzing changes in astronomical objects
- transient: observed change in the sky
Transient High Energy Sky and Early Universe Surveyor (THESEUS): plan for X-ray/Gamma-ray transient space mission
transient lunar phenomenon (lunar transient phenomenon): observed transient on the Moon such as a flash of light
Transient Name Server: online catalog of transients
- fast radio burst: astronomical high energy radio pulses of a few milliseconds
- supernova designator: typical designation of supernovae
transient type

black hole merger: two black holes meeting and forming one
calcium-rich gap transient: type of explosive event larger than a nova and smaller than a supernova
cataclysmic variable star: star whose magnitude is much brighter on occasion
Cepheid variable: type of star that varies with a constant period
core collapse supernova: supernova resulting from the collapse of the core of a star
double transit: star showing transits of two bodies
dust echo: the glow of dust heated by a transient
dwarf nova: flash of a cataclysmic variable star
electron capture supernova: supernova from collapse of iron-free stellar cores
fast blue optical transient: optical transient with rise time under five days
fast radio burst: astronomical high energy radio pulses of a few milliseconds
gamma-ray burst: short flash of gamma rays apparently from outside our galaxy
gravitational microlensing: gravitational lensing by "small" objects such as individual stars and planets
GRB-supernova: supernova that produces a GRB
GW detection: observed gravitational wave signal recognizable as an astronomical event
intermediate luminosity optical transient: visible-light transient a bit brighter than a nova
kilonova: transient associated with merging neutron stars
light echo: reflected light from an astronomical event arriving later
long gamma-ray burst: GRB lasting more than two seconds
luminous red nova: red-colored event theorized to be a merger of two stars
magnetorotational supernova: type of core collapse supernova
near-Earth supernova: supernova near enough to Earth to affect it
neutron star merger: two neutron stars meeting and forming one
neutron-star black-hole merger: a neutron star falling into a black hole
nova: white dwarf explosion
occultation: one celestial body hiding another from an observer
pair-instability supernova: type of large supernova
pulsating star: variable star that varies through energy pulses
radio supernova: supernova that includes a detectable radio emission
RR Lyrae variable: star with periodic variation often in globular clusters
secondary eclipse: eclipse of a body that also transits
short gamma-ray burst: GRB lasting less than two seconds
superluminous supernova: stellar explosion larger than a supernova
supernova: stellar explosion larger than a nova
supernova impostor: extreme stellar explosion that does not destroy the star
tidal disruption event: star pulled apart by black hole tidal forces
transit: a celestial body passing between another and an observer
transiting planet: planet crossing between another body and the observer
Type Ia supernova: type of supernova for which distance can be determined
variable star: star that varies in magnitude
Wolf-Rayet supernova: identified by rapidly expanding carbon, oxygen and neon
X-ray flash: short flash of X-rays

transients

All Sky Automated Survey: Polish survey of 20 million objects brighter than 14 magnitude
All Sky Automated Survey for SuperNovae: survey of both hemispheres for supernovae
Calán/Tololo Supernova Survey: late 1980s to early 1990s search to redshift 0.1
Canadian Hydrogen Intensity Mapping Experiment: radio telescope mapping distant neutral hydrogen
CFHTLS: surveys of transients and stars
Compton Gamma Ray Observatory: 1990s space observatory for gamma ray observation
Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey: early-universe survey by HST
drift scan: method of observing substantial sky with CCDs
DSA-2000: array plan to detect radio transients
electronic very-long-baseline interferometry: real-time VLBI using electronic links
EROS: search for MACHOs
Evryscope: automated array of telescopes to uncover transients
FRB Community Newsletter: periodical message about fast radio bursts
Gamow Explorer: proposal for GRB space mission
Gattini-IR: IR transient survey telescope
GCRT: galactic center radio transient
GMAN: collaboration to alert on microlensing transients
guest star: translation of ancient Chinese term for a visible transient
HATNet: distributed array of telescopes to search for transients
High Energy Transient Explorer: 2000s space multi-band GRB observatory
high time-resolution astrophysics: second-by-second observation of/for transients
K2: second Kepler mission that worked around failed equipment
KELT: pair of telescopes that searched for transients
Kepler Telescope: space telescope that watched stars for exoplanets
Korea Microlensing Telescope Network: survey searching for microlensing transients
Lick Observatory Supernova Search: search for supernovae for cosmological study
light curve: changing intensity of light from a transient
lightkurve: software to analyze time series data
Livermore Optical Transient Imaging System: automated telescope aiming to catch GRB optical counterparts
MACHO Project: survey searching out microlensing that could indicate a MACHO
MASCARA: distributed array of telescopes to search for exoplanets
MAXI: Japanese X-ray camera on the International Space Station
MicroFUN: observers following up on microlensing events in the galactic bulge
MISAO project: search for variable stars and transients
MIT X-ray Burst Source Catalog: 1970s catalog of X-ray bursters
MOA: search for microlensing events
MOSFiT: code to match light-curves with light-curve models
Nearby Supernova Factory: survey that scanned transient data for supernovae
NGTS: survey of transits from Chile
OGLE: survey searching for microlensing transients
Palomar Transient Factory: survey designed to find transients
Pan-STARRS: set of survey telescopes
Period04: software to identify periods in time series data
PESSTO: NTT survey following up on transients
Pi of the Sky: survey aimed at finding gamma-ray-burst visual counterparts
PLATO: planned observatory-satellite aimed at finding exoplanets
POINT-AGAPE: survey of M31 for microlensing
Probing Lensing Anomalies Network: survey that recorded microlensing event lightcurves
Qatar Exoplanet Survey: photometric survey that searched for transiting planets
QUEST: sixteen square-degree survey camera
RAPTOR: automated array of telescopes to uncover and track transients
Roman Space Telescope: proposed near-infrared space observatory
rotating radio transient: radio bursts repeating sporadically
ROTSE: automated array of telescopes to uncover and track transients
Rubin Observatory: 8-meter survey reflector telescope under construction in Chile
SPIRITS: Spitzer survey designed to find transients
STARE: array of radio telescopes monitoring radio transients
STEREO: two-satellite system to observe the Sun
supernova light curve: changing intensity of light following a supernova
TAROT: network of telescopes to catch GRB optical counterparts
THESEUS: plan for X-ray/Gamma-ray transient space mission
Tianlai Project: 21-cm line intensity mapping project
time-domain astronomy: observing and analyzing changes in astronomical objects
Trans-Atlantic Exoplanet Survey: 2000s exoplanet-search survey using three telescopes
transient astronomy: study of short-term astronomical phenomena
Transient Name Server: online catalog of transients
Transiting Exoplanet Survey Satellite: observatory-satellite searching for transiting exoplanets
ULTRASAT: future satellite to detect UV transients
X-ray burster: neutron star binary producing nova-like bursts
XO Project: initiative to search for transiting planets
Zwicky Transient Facility: survey designed to find transients

transit: a celestial body passing between another and an observer
transit: see meridian circle
transit: see transit telescope
- occultation: one celestial body hiding another from an observer
transit circle (meridian circle): instrument for timing the passage of stars over a meridian
transit depth: see transiting planet
transit duration: see transiting planet
transit duration variations: see transit timing variations
- exosatellite: natural satellite not in the solar system
transit mapping: see eclipse mapping
transit method: method of detecting exoplanets and binary companions
transit method: see extra-solar planet
transit method: see transit
- EXOFAST: code to match model parameters with exoplanet observation data
- GJ 1132 b: Earth-like extrasolar planet discovered in 2015
- GJ 1214 b: super-Earth extrasolar planet discovered in 2009
- HAT-P-7b: hot Jupiter discovered in 2008
- HD 189733 b: hot Jupiter orbiting an orange dwarf
- K2-18b: super-Earth in a habitable zone
- Kepler-1625b: giant exoplanet in a star's habitable zone
- Kepler-16b: exoplanet orbiting a binary star
- Kepler-186f: Earth-like exoplanet in a star's habitable zone
- Kepler-452b: Earth-like exoplanet discovered in 2015
- LHS 3844 b: rocky planet in habitable zone of a red dwarf
- TOI 700 d: Earth-sized exoplanet in a habitable zone
- transiting planet: planet crossing between another body and the observer
- WASP-12b: retrograde hot Jupiter discovered in 2008
- WASP-33b: hot Jupiter discovered in 2010
- WASP-43b: hot Jupiter with especially small orbit
- WASP-67b: hot Jupiter discovered in 2011
- XO-3b: unusual hot Jupiter
transit radio telescope

transit telescope: telescope able to shift aim up/down but not horizontally

transit spectrography (transit spectroscopy): spectroscopy through an exoplanet's transit
transit spectrometer: see transit spectroscopy
transit spectroscopy: spectroscopy through an exoplanet's transit
- differential spectroscopy: analysis of the comparison of two spectrographs
- earthshine: reflected and emitted electromagnetic radiation from Earth
transit telescope: telescope able to shift aim up/down but not horizontally
- meridian circle: instrument for timing the passage of stars over a meridian
transit timing variations: variations in the timing of the transits of exoplanets and binaries
transiting exoplanet: see transiting planet
Transiting Exoplanet Survey Satellite: observatory-satellite searching for transiting exoplanets
transiting planet: planet crossing between another body and the observer
- transit: a celestial body passing between another and an observer
Transiting Planets and Planetesimals Small Telescope (TRAPPIST): a ground-based automated transiting-planet finding telescope
transition disk (transitional disk): disk with inner part cleared
transition edge sensor: sensor using superconductivity's strong temperature sensitivity
transition edge sensor bolometer: see transition edge sensor
transition region: middle layer of the Sun's atmosphere
- chromosphere: middle layer of the Sun's atmosphere
- stellar atmosphere: photosphere and above
Transition Region and Coronal Explorer (TRACE): former solar observing satellite
transitional disk: disk with inner part cleared
transitional planet (mini-Neptune): planet with characteristics a bit like Earth but more like Neptune
transitional planet: see super-Earth
transits

55 Cancri e: super-Earth orbiting a Sun-like star
batman: code to calculate model transit lightcurves
CHEOPS: space telescope in development to measure radii of exoplanets
COROT: observatory-satellite to look for transiting exoplanets and stellar oscillations
eclipse mapping: using eclipse light curves to map surface features
exoplanet eclipse light curve: graph of light as an exoplanet transits in front of its star
GPX: amateur effort to uncover exoplanets within the galactic plane
HATNet: distributed array of telescopes to search for transients
HD 209458 b: hot Jupiter discovered in 1999
HD 80606 b: hot Jupiter discovered in 2001
K2: second Kepler mission that worked around failed equipment
KELT: pair of telescopes that searched for transients
Kepler Telescope: space telescope that watched stars for exoplanets
Lupus Transit Survey: survey for hot Jupiters in a region of constellation Lupus
MASCARA: distributed array of telescopes to search for exoplanets
MEarth Project: automated observatories monitoring nearby red dwarfs for transits
NGTS: survey of transits from Chile
PLATO: planned observatory-satellite aimed at finding exoplanets
Pre-OmegaTranS: transit search using MPG/ESO Telescope
Qatar Exoplanet Survey: photometric survey that searched for transiting planets
Rossiter-McLaughlin effect: effect of transit on visible spectrum of the star
Sagittarius Window Eclipsing Extrasolar Planet Search: transit search using HST time
SPECULOOS: search for Earth-like exoplanets orbiting nearby dim stars
Trans-Atlantic Exoplanet Survey: 2000s exoplanet-search survey using three telescopes
transit method: method of detecting exoplanets and binary companions
transit timing variations: variations in the timing of the transits of exoplanets and binaries
Transiting Exoplanet Survey Satellite: observatory-satellite searching for transiting exoplanets
transiting planet: planet crossing between another body and the observer
WFCAM Transit Survey: 2000s survey for exoplanet transits using UKIRT
XO Project: initiative to search for transiting planets

Transits of Extrasolar Planets: late 1990s search for transiting planets
transmission spectrography (transmission spectroscopy): spectrum of radiation passing through a substance
transmission spectroscopy: spectrum of radiation passing through a substance
- transit spectroscopy: spectroscopy through an exoplanet's transit
transmissive grating: see grating
transonic: see Mach number
transport-limited: see weathering
transverse velocity: see radial velocity
Trapezium Cluster: open cluster of stars in Orion Nebula
TRAPPIST: a ground-based automated transiting-planet finding telescope
TRAPPIST telescope

La Silla Observatory: Atacama-desert observatory run by ESO

TRAPPIST-1: red dwarf with exoplanets within the habitable zone
TRAPPIST-1b: see TRAPPIST-1
TRAPPIST-1c: see TRAPPIST-1
TRAPPIST-1d: see TRAPPIST-1
TRAPPIST-1e: see TRAPPIST-1
TRAPPIST-1f: see TRAPPIST-1
TRAPPIST-1g: see TRAPPIST-1
TRAPPIST-1h: see TRAPPIST-1
TRAPPIST-North: see TRAPPIST
TRAPPIST-South: see TRAPPIST
Traverse Gravimeter Experiment

gravimetry: measurement of gravity's strength

TRC: see Hipparcos
treasury: see legacy survey
Treasury Program: see legacy survey
treasury survey: see legacy survey
tree

dendrogram: diagram of a "tree", i.e., of a graph without cycles

tremendously low frequency: presumably electromagnetic radiation, frequency below 3 Hz
TrES (Trans-Atlantic Exoplanet Survey): 2000s exoplanet-search survey using three telescopes
TRGB (tip of the red-giant branch): standard candle consisting of the brightest RGB stars
Tri II (Triangulum II): dwarf galaxy in the Local Group
Triana (DISCOVR): space weather satellite
Triangulum (Triangulum Galaxy): small spiral galaxy in the Local Group
Triangulum Galaxy: small spiral galaxy in the Local Group
Triangulum II: dwarf galaxy in the Local Group
- Milky Way subgroup: the Milky Way and its satellites
Triangulum subgroup

galaxy subgroup: a major galaxy and its satellites

triaxial

spheroid: sphere-like shape that is flattened or elongated

triaxial galaxy

galaxy: gravitationally-bound group of stars
Jeans anisotropic modeling: method of determining stellar kinematics of early type galaxies

trigonometric parallax (parallax): angle due to different lines of sight
triple alpha process: fusion reaction chain turning helium-4 into carbon
- asymptotic giant branch: a second stage of helium burning in some stars
triple bond: see hydrocarbon
triple point

Mars: well-explored planet in the solar system
supercritical fluid: state of matter at sufficient pressure and temperature

triple prism spectrograph: see spectroscopy
triple star: see star system
triple system

black hole merger: two black holes meeting and forming one

TripleSpec: near-infrared spectrograph on the Hale Telescope
TripleSpec: see Hale Telescope
TripleSpec 4.1: see SOAR Telescope
TripleSpec 4.1: see TripleSpec
Triplespec 4.1: see Víctor M. Blanco Telescope
TripleSpec Exoplanet Discovery Instrument: see TripleSpec
TripleSpec Externally Dispersed Interferometry: see TripleSpec
tritium: see deuterium
tritium: see hydrogen
- KATRIN: experiment to measure neutrino mass
- Project 8: experiment in development to measure neutrino mass
Triton: Neptune's one significant moon
Triton: see Neptune
- irregular moon: moon with an atypical orbit, such as retrograde
- moon: a planet's natural satellite, such as Earth's
- Moon formation: process by which the Moon and other moons formed
Trojan: see asteroid belt
- Lagrangian point: points around two orbiting bodies where small objects can sit
Trojan asteroid: see asteroid belt
- Lagrangian point: points around two orbiting bodies where small objects can sit
- Lucy: space probe to observe Jupiter Trojan asteroids
Trojan planet: see Lagrangian point
Trojan point: see Lagrangian point
- Lucy: space probe to observe Jupiter Trojan asteroids
Trojans' Odyssey (Lucy): space probe to observe Jupiter Trojan asteroids
Tropic of Cancer: see circle of latitude
Tropic of Capricorn: see circle of latitude
tropical year: see Julian calendar
tropical year: see sidereal
tropopause: see atmospheric temperature profile
troposphere: see atmospheric temperature profile
true anomaly: see mean anomaly
- orbital element: parameters describing an orbit
true vacuum: see false vacuum
- Big Crunch: theoretical end of universe drawn together by gravity
Trumpler: see rare designator prefixes
TS: see rare designator prefixes
Tsol: see Titan
TSpec (TripleSpec): near-infrared spectrograph on the Hale Telescope
tsunami

mass extinction: event in which many species went extinct

TSUNAMI: few-body code
tSZ: see Sunyaev-Zel'dovich effect
tSZE: see Sunyaev-Zel'dovich effect
TT (Terrestrial Time): current measure of time for astronomical observations on Earth
TT: see CMB polarization
TT: see time standard
TTCam: see Lucy
TTCam-1: see Lucy
TTCam-2: see Lucy
TTM: see Kvant 1
TTS (T-Tauri star): type of variable pre-main-sequence star
- DM Tau: nearby T-Tauri star
- DQ Tau: young binary star system
- GG Tau: much-studied quadruple star system
- Herbig AeBe star: type of pre-main-sequence star more massive than a T-Tauri star
- HL Tau: much-studied T-Tauri star
- PDS 70: T-Tauri star with protoplanetary disk and protoplanet
- pre-main-sequence star: star not yet with a nuclear reaction
- RXJ1615: protostar with transition disk showing rings
- T association: stellar association with T-Tauri stars
- TW Hydrae: nearest T-Tauri star
TTV (transit timing variations): variations in the timing of the transits of exoplanets and binaries
TTV method: see transit timing variations
Tubingen Ultraviolet Echelle Spectrometer: 1990s UV spectrometer used on two Space Shuttle missions
Tuc-Hor (Tucana Horologium association): nearby stellar association
Tucana Horologium association: nearby stellar association
TUES (Tubingen Ultraviolet Echelle Spectrometer): 1990s UV spectrometer used on two Space Shuttle missions
Tully-Fisher relation: relation between spiral galaxy luminosity and line width
TuMAG: see SUNRISE
tuning fork: see galaxy classification
Tunka Advanced Instrument for cosmic ray physics and Gamma Astronomy (Tunka experiment): Russian Cherenkov detector aimed at cosmic rays and gamma rays
Tunka experiment: Russian Cherenkov detector aimed at cosmic rays and gamma rays
tunnel diode

quantum tunneling: quantum mechanical effect of particles passing through a barrier

tunneling (quantum tunneling): quantum mechanical effect of particles passing through a barrier
turbopause (homopause): level of atmosphere up to which components are mixed
turbulence: irregular flow of a fluid
- Kolmogorov spectrum: energy spectrum of the eddies of different sizes in a turbulent fluid
- Mach number: ratio of flow-speed to sound-speed
- molecular cloud turbulence: observed turbulence in molecular clouds
- Rayleigh number: measure reflecting a fluid system's propensity to convection
- Reynolds number: measure reflecting a fluid system's propensity to turbulence
- seeing: apparent blurring and twinkling of objects seen through atmosphere
- turbulent pressure: pressure component due to the presence of turbulence
turbulence pressure (turbulent pressure): pressure component due to the presence of turbulence
turbulent flow (turbulence): irregular flow of a fluid
turbulent pressure: pressure component due to the presence of turbulence
turn-off (turn-off point): point in H-R diagram of a cluster where stars turn red
turn-off point: point in H-R diagram of a cluster where stars turn red
Turner: see rare designator prefixes
Turtlebeach: radiative transfer code
TVLM: see rare designator prefixes
TW Hya (TW Hydrae): nearest T-Tauri star
TW Hydrae: nearest T-Tauri star
- TW Hydrae association: nearby stellar association
TW Hydrae association: nearby stellar association
TW-1 (Tianwen-1): active Chinese Mars rover/orbiter mission
TWA (TW Hydrae association): nearby stellar association
TWA star: see TW Hydrae association
Twin Astrograph Catalog: see USNO Twin Astrograph
twinkle

point source: celestial object that focuses to a point or single Airy disk

twinkling: blinking, apparent movement and color changes of observed stars
- scintillometry: measuring of twinkling
two dimensional model: see three dimensional model
- subgrid-scale physics: shortcuts handling physics on a smaller scale than a simulation's grid
Two Micron All-sky Survey: near-infrared survey of both hemispheres
- JHK photometric system: system to classify stars according to near-infrared colors
Two Micron Sky Survey: 1969 infrared catalog produced by Caltech
two-body problem: see N-body problem
two-line element set: data format to record the position and motion of a satellite
two-photon emission: see continuum emission
two-stream approximation: approximation of a star's internal EMR's divergence from isotropic
- Eddington approximation: approximation of a star's internal EMR's divergence from isotropic
- Schuster-Schwarzschild model: simplified model of a star's production of absorption lines
twotino: see plutoid
TXFS: see rare designator prefixes
TXS (Texas Survey of Radio Sources at 365 MHz): 1970s/1980s radio survey made with the Texas Interferometer
TXS 0506+056: blazar that is a neutrino source
- neutrino hotspot: region of sky from which significant neutrinos have been detected
TYC: see Hipparcos
TYCHO: stellar evolution code
Tycho Catalog: see Hipparcos
Tycho Input Catalog: see Hipparcos
Tycho Reference Catalog: see Hipparcos
Tycho SNR: see SN 1572
Tycho's Supernova (SN 1572): Type Ia supernova noted in 1572 by Tycho Brahe
Tycho's supernova

Cassiopeia A: supernova remnant visible for 300 years

Tycho-1 Catalog: see Hipparcos
Tycho-2 Catalog: see Hipparcos
Type 1 AGN: see active galactic nucleus
- Seyfert galaxy: visible active galaxy
Type 1 Seyfert galaxy: see Seyfert galaxy
Type 2 AGN: see active galactic nucleus
- Seyfert galaxy: visible active galaxy
Type 2 Seyfert galaxy: see Seyfert galaxy
Type 3 Seyfert galaxy: see Seyfert galaxy
- LINER: galaxy nucleus emitting spectral lines for ionized and neutral atoms
Type A CAI: see CAI
Type B CAI: see CAI
Type C CAI: see CAI
Type I Cepheid: see Cepheid variable
Type I galaxy cluster: see Bautz-Morgan classification
Type I migration: see planetary migration
- corotation resonance: orbit resonant with a nearby high-density portion of a disk
- corotation torque: a torque on a planet from co-orbiting planetary disk material
- magnetorotational instability: instability in the fluid of a disk from MHD effects
Type I SLSN: see superluminous supernova
Type I supernova

supernova: stellar explosion larger than a nova
Type Ia supernova: type of supernova for which distance can be determined

Type I-II galaxy cluster: see Bautz-Morgan classification
Type Ia supernova: type of supernova for which distance can be determined
- alpha-enhanced: metallicity with a high percentage of alpha elements
- SN 185: supernova recorded in China in AD 185
- supernova: stellar explosion larger than a nova
- supernova progenitor: the star or star system that produces a supernova
- T Pyxidis: well-known recurrent nova
- Type Ia supernova problem: lack of fully-convincing Type Ia supernovae triggering model
Type Ia supernova problem: lack of fully-convincing Type Ia supernovae triggering model
Type Ia supernova progenitor: see supernova progenitor
- Type Ia supernova problem: lack of fully-convincing Type Ia supernovae triggering model
Type Ia supernova survey: see supernova survey
Type Ib supernova: see core collapse supernova
Type Ib supernova: see supernova
Type Ic BL supernova

long gamma-ray burst: GRB lasting more than two seconds

Type Ic supernova: see core collapse supernova
Type Ic supernova: see supernova
- superluminous supernova: stellar explosion larger than a supernova
Type II Cepheid: see Cepheid variable
Type II galaxy cluster: see Bautz-Morgan classification
Type II migration: see planetary migration
Type II SLSN: see superluminous supernova
Type II supernova (core collapse supernova): supernova resulting from the collapse of the core of a star
- supernova: stellar explosion larger than a nova
Type II-III galaxy cluster: see Bautz-Morgan classification
Type II-L supernova: see supernova
Type II-P supernova: see supernova
Type IIb: see supernova
Type III galaxy cluster: see Bautz-Morgan classification
Type III migration: see planetary migration
Type IIIE galaxy cluster: see Bautz-Morgan classification
Type IIIS galaxy cluster: see Bautz-Morgan classification
Type IIn supernova: see supernova
- superluminous supernova: stellar explosion larger than a supernova
TZO (Thorne-Żytkow object): giant star with a neutron star at its center

Index