Term Index (N)
Astrophysical terms and names of things beginning with the letter N.
N3
N7
NA
NB
NC
ND
NE
NF
NG
NH
NI
NL
NM
NN
NO
NP
NR
NS
NT
NU
NV
NW
NY
NZ
- N (nitrogen): metal, N, atomic number 7
- N (nova): white dwarf explosion
- N (particle number): number of particles
- N: see filter designator
- N: see rare designator prefixes
- n (number density): number of objects per volume
- n: see electron orbital
- n: see electron shell
- N 103B: supernova remnant in the LMC
- N band: see infrared
- mid infrared: infrared radiation with wavelengths in the 7.5-25 μm range
- N galaxy: galaxy with bright nucleus and faint surroundings
- Nāmakanui: see James Clerk Maxwell Telescope
- N-body (N-body simulation): simulation of many objects gravitationally-bound to each other
- N-body problem: calculating the paths of gravitationally-interacting celestial objects
- N-body simulation: simulation of many objects gravitationally-bound to each other
- n-NSE: see nuclear statistical equilibrium
- N-PDF: see probability density function
- N-point correlation function (N-point function): general term for analyses-techniques of spatial data
- N-point function: general term for analyses-techniques of spatial data
- N30: see N30 Catalog
- N30 Catalog: 1950s catalog collecting proper motion data from older catalogs
- N747NA: see SOFIA
- N500: see cluster radius
- NA (Avogadro's number): number of hydrogen atoms per gram
- Neff: see neutrino
- NHe: see particle number
- NHI: see particle number
- ns: see Lambda-CDM model
- Na (sodium): metal, Na, atomic number 11
- Na: see rare designator prefixes
- NAB: see rare designator prefixes
- nabla: see gradient
- NACA: see NASA
- NACO: see European Southern Observatory Very Large Telescope
- nadir: see zenith
- NAI (NASA Astrobiology Institute): former research funding and coordination organization
- NAIC (Arecibo Observatory): former large 305 m radio telescope in Puerto Rico
- naked singularity: see gravitational singularity
- naked T-Tauri star: see T-Tauri star
- Namaka: see Haumea
- Namibia
- NAMN (North American Meteor Network): former group of amateurs with an interest in meteors
- Nançay Radio Telescope: large radio telescope in France
- Nancy Grace Roman Space Telescope (Roman Space Telescope): proposed near-infrared space observatory
- NANOGrav: effort to detect gravitational waves through pulsar timing
- nanohertz gravitational waves: size of GWs that pulsar-timing observations might catch
- nanohertz GWs (nanohertz gravitational waves): size of GWs that pulsar-timing observations might catch
- nanolensing: see gravitational microlensing
- nanomaggie: a billionth of an AB magnitude
- nanometer
- nanosat (nanosatellite): NASA term for a 1-10 kg small satellite
- nanosatellite: NASA term for a 1-10 kg small satellite
- nanotesla: see tesla
- NANTEN: see NANTEN2
- NANTEN-2
- NANTEN2: millimeter telescope in Chile
- Atacama Desert: Chilean high-altitude, dry plateau with numerous observatories
- NAOC
- NAOJ (National Astronomical Observatory of Japan): Japanese astronomy organization
- NAOMI: see European Southern Observatory Very Large Telescope
- NAOMI: see William Herschel Telescope
- Narrabri Observatory
- Narrabri Stellar Intensity Interferometer: 1960s optical interferometer for measuring stellar diameters
- narrow band: see passband
- narrow band filter: see passband
- narrow band photometry: see photometry
- narrow emission-line region (narrow line region): AGN region producing narrower lines
- narrow line AGN
- narrow line region: AGN region producing narrower lines
- narrow-line radio galaxy: see radio galaxy
- narrow-line region
- narrowband: see bandwidth
- NARVAL
- NAS (National Acadamy of Sciences): US organization of distinguished scientists
- NAS (Norsk Astronomisk Selskap): Norwegian non-profit association of astronomers
- NASA: includes space-based astronomy research
- NASA Astrobiology Institute: former research funding and coordination organization
- NASA Deep Space Network: NASA's world-wide radio communication setup
- NASA DSN (NASA Deep Space Network): NASA's world-wide radio communication setup
- NASA Exoplanet Archive: online database of exoplanets
- NASA Flagship Program
- HabEx: proposed space mission to directly image exoplanets
- NASA Infrared Telescope Facility (IRTF): Mauna Kea 3-meter infrared telescope
- NASA IRTF (IRTF): Mauna Kea 3-meter infrared telescope
- NASA Orbital Debris Observatory: 1990s telescope aimed at tracking space junk
- NASA Space Science Data Coordinated Archive: NASA archive of flight information and astronomy findings
- NASA Standard Breakup Model: model maintained by NASA of how satellites fragment
- NASA/IPAC Extragalactic Database: a database of galaxies and other objects outside the Milky Way
- NASA/IPAC Infrared Science Archive (IRSA): archive center for infrared data from NASA missions
- NASA747: see SOFIA
- NASDA: see Japan Aerospace Exploration Agency
- NASEM (National Academies of Sciences, Engineering, and Medicine): US collective of three national acadamies
- Nasmyth telescope: type of reflector telescope with secondary and tertiary mirrors
- Nasmyth-Cassegrain telescope (Nasmyth telescope): type of reflector telescope with secondary and tertiary mirrors
- NASTec (International Small Telescope Cooperative): former cooperative of small research telescopes
- NaTeCam: see Tianwen-1
- National Acadamy of Sciences: US organization of distinguished scientists
- National Academies of Sciences, Engineering, and Medicine: US collective of three national acadamies
- National Advisory Committee on Aeronautics: see NASA
- National Aeronautics and Space Administration (NASA): includes space-based astronomy research
- National Astronomical Observatories of China
- National Astronomical Observatory
- SPECULOOS: search for Earth-like exoplanets orbiting nearby dim stars
- National Astronomical Observatory of Japan: Japanese astronomy organization
- National Astronomy and Ionosphere Center (Arecibo Observatory): former large 305 m radio telescope in Puerto Rico
- National Bureau of Standards: name of of NIST before 1988
- National Center for Atmospheric Research
- National Center for Supercomputer Applications
- Partiview: visualization software aimed at 4D data
- National Geographic Society-Palomar Observatory Sky Survey (Palomar Observatory Sky Survey): 1950s photographic plates from Palomar 48 inch telescope
- National Institute of Standards and Technology: US agency defining standards
- National Oceanic and Atmospheric Administration: US meteorology and oceanography agency
- SWFO-L1: future NOAA space-weather warning satellite
- National Optical Astronomy Observatory: previous name of US optical astronomy organization
- National Optical-Infrared Astronomy Research Laboratory (NOIRLab): US optical/infrared astronomy organization
- National Radio Astronomy Observatory: US radio astronomy organization
- National Radio Quiet Zone: see Green Bank Observatory
- dark sky: sky with limited light pollution
- National Reconnaissance Office
- National Research Council (Consiglio Nazionale delle Ricerche): Italian national research organization.
- National Science Foundation: US government organization funding scientific research
- National Solar Observatory: US government sponsored solar observatory
- National Space Development Agency: see Japan Aerospace Exploration Agency
- National Space Science Data Center (NASA Space Science Data Coordinated Archive): NASA archive of flight information and astronomy findings
- natural astronomical telescopes: use of an astronomical body as a telescope
- natural broadening: line broadening due to uncertainty principle
- natural broadening: see line broadening
- natural guide star: see guide star
- natural laser: see coherent light
- natural satellite: see moon
- natural satellites
- natural units: see Planck units
- Naval Observatory Merged Astrometric Dataset (NOMAD): astrometric star catalog
- Naval Research Laboratory: US Navy scientific research arm
- Navarro-Frenk-White profile: a dark matter spatial mass distribution function
- Navcam: see Mars Exploration Rover
- Navcams: see Mars Science Laboratory
- Navier-Stokes equations: equations that describe fluid dynamics
- Navy Optical Interferometer
- Navy Precision Optical Interferometer: optical interferometer in Arizona
- Navy Prototype Optical Interferometer (Navy Precision Optical Interferometer): optical interferometer in Arizona
- NB: see rare designator prefixes
- NBODY: code to carry out N-body simulations
- NBODY6: see NBODY
- NBODY7: see NBODY
- NBS (National Bureau of Standards): name of of NIST before 1988
- NC: see Stardust
- NC meteorite: see carbonaceous chondrite
- NCAR
- NCE: see chemical equilibrium
- NCSA
- Partiview: visualization software aimed at 4D data
- NDWFS (NOAO Deep Wide-field Survey): survey investigating large scale structure of the universe
- Ne (neon): element, Ne, atomic number 10
- NEA: see near-Earth object
- NEAP (Near Earth Asteroid Prospector): planned space mission to look at NEOs as mining sources
- NEAR (NEAR Shoemaker): space mission to an asteroid
- near earth
- near Earth asteroid
- 2010 TK7: asteroid that is an Earth Trojan
- near earth asteroid
- Near Earth Asteroid Prospector: planned space mission to look at NEOs as mining sources
- Near Earth Asteroid Rendezvous (NEAR Shoemaker): space mission to an asteroid
- near earth object
- NEO Surveyor: planned space observatory to detect and monitor NEOs
- Near Earth Object WISE: see Wide-field Infrared Survey Explorer
- Near Earth Objects Dynamic Site (NEODyS): web service to providing information on NEOs
- Near Earth Objects Information Centre (Spaceguard Centre): UK private observatory dedicated to NEOs
- Near Earth Space Surveillance (NEOSSat): small spacecraft tracking NEOs
- near infrared: electromagnetic radiation in the range of 750-2500 nm
- Near Infrared Camera (NIRCam): near infrared imager on JWST
- Near Infrared Planet Searcher (NIRPS): near-infrared extension to HARPS spectrograph
- Near Infrared Planet Searcher: see ESO 3.6m Telescope
- Near Infrared Spectrograph (NIRSpec): near infrared spectrograph on JWST
- NEAR Shoemaker: space mission to an asteroid
- near ultraviolet: see ultraviolet
- optics: science and technology regarding visible light
- ULTRASAT: future satellite to detect UV transients
- near-Earth asteroid: see near-Earth object
- Near-Earth Asteroid Tracking (NEAT): survey tracking near-Earth objects
- near-Earth object: object orbiting the Sun that passes close to Earth
- 101955 Bennu: near-Earth asteroid that is the target of a sample-return mission
- Pan-STARRS: set of survey telescopes
- Near-Earth Object Camera (NEO Surveyor): planned space observatory to detect and monitor NEOs
- Near-Earth Object Surveillance Mission (NEO Surveyor): planned space observatory to detect and monitor NEOs
- Near-Earth Object Surveillance Satellite (NEOSSat): small spacecraft tracking NEOs
- CSA: includes astronomical research
- Near-Earth Object Surveyor (NEO Surveyor): planned space observatory to detect and monitor NEOs
- near-Earth objects
- near-earth objects
- near-Earth supernova: supernova near enough to Earth to affect it
- Near-infrared Echelle for Wide-band Spectroscopy (NEWS): planned near-infrared spectrometer on Discovery Channel Telescope
- near-IR (near infrared): electromagnetic radiation in the range of 750-2500 nm
- near-UV: see ultraviolet
- nearby star
- Nearby Supernova Factory: survey that scanned transient data for supernovae
- Nearby Supernova Factory II: see Nearby Supernova Factory
- NEAT: survey tracking near-Earth objects
- NEAT: see James Webb Space Telescope
- nebula: cloud of dust and gas
- nebulae
- nebular hypothesis: model positing solar system planets result from a solar disk
- nebular line (forbidden line): spectral line that quantum mechanics disallows for the most part
- nebular shock: see chondrite
- NED (NASA/IPAC Extragalactic Database): a database of galaxies and other objects outside the Milky Way
- Nederlandse Organisatie voor Wetenschappelijk Onderzoek: Dutch research council
- negative absorption: see emission coefficient
- negative feedback
- negative gravity anomaly: see gravity anomaly
- negative redshift (blue shift): shortening of wavelengths due to Doppler effects
- negative-pressure vacuum energy density: see inflation
- NEID: see WIYN 3.5m Telescope
- Neil Gehrels Swift Observatory (Swift): satellite for studying gamma-ray bursts
- NELM: naked eye limiting magnitude
- NEMESIS: see atmospheric model
- NEMO: see KM3NeT
- NEMO-3: see KM3NeT
- NEMP: see carbon star
- NEO (near-Earth object): object orbiting the Sun that passes close to Earth
- NEO Surveyor: planned space observatory to detect and monitor NEOs
- NEOCam (NEO Surveyor): planned space observatory to detect and monitor NEOs
- neodymium
- NEODyS: web service to providing information on NEOs
- NEOIC (Spaceguard Centre): UK private observatory dedicated to NEOs
- neon: element, Ne, atomic number 10
- neon burning: fusion reaction starting with neon
- neon-burning shell: see neon burning
- NEOs
- NEOSM (NEO Surveyor): planned space observatory to detect and monitor NEOs
- NEOSSat: small spacecraft tracking NEOs
- CSA: includes astronomical research
- NEOWISE: see Wide-field Infrared Survey Explorer
- NEO Surveyor: planned space observatory to detect and monitor NEOs
- NEP (noise-equivalent power): signal power that equals the noise
- Neptune: outer-most solar system planet
- ethylene: compound of two carbon and four hydrogen atoms
- giant planet: planet of more than 10 Earth masses
- ice giant: planet denser than gas planets and less than rocky planets
- ring system: disk or set of rings orbiting a planet
- shepherd moon: small moon affecting outer edge of a planet's ring
- solar system object: the Sun, solar system planets, minor planets, comets, and moons
- Triton: Neptune's one significant moon
- Voyager: space probes to observe planets and the edge of the solar system
- Neptune desert: Neptune-like exoplanets near host star are rare
- Neptune I (Triton): Neptune's one significant moon
- Neptune Trojan: see asteroid belt
- Neptunes: see extra-solar planet
- Neptunian desert (Neptune desert): Neptune-like exoplanets near host star are rare
- NES: see Large Altazimuth Telescope
- NESS (NEOSSat): small spacecraft tracking NEOs
- NESSI (The Near Earth Space Surveillance Initiative): collaboration to survey NEOs
- Nessie: star-forming filament found in the Orion star-forming region
- Nessie Nebula (Nessie): star-forming filament found in the Orion star-forming region
- nested Maclaurin spheroids
- nested sampling: see dynesty
- NESTOR: see KM3NeT
- Netherlands
- Netherlands Institute for Radio Astronomy (ASTRON): Netherlands radio astronomy research organization
- Netherlands Organisation for Scientific Research
- ASTRON: Netherlands radio astronomy research organization
- neural network: computer program structure inspired by the brain
- neural networks
- neuron
- neutral atom: see state of ionization
- ion: non-neutral atom or molecule, with missing or extra electrons
- neutral atomic hydrogen: state of hydrogen when sufficiently cool
- neutral current interaction: see weak interaction
- neutral tail: see comet
- neutralino: proposed type of particle that might include WIMPs
- dark matter: matter in galaxies and galaxy clusters suggested by their gravity
- PICO experiment: a search for a candidate dark matter particle
- neutrino: light, electrically neutral elementary particle
- dark matter: matter in galaxies and galaxy clusters suggested by their gravity
- flavor: subtype of some type of particle
- lepton: elementary particle with 1/2 integer spin such as electron
- neutronization: an electron and proton combining to form a neutron
- particle: very small thing
- supersymmetry: extension to standard model of particle physics
- WIMP: proposed particle comprising dark matter
- neutrino astronomy: see neutrino
- neutrino cooling: see neutrino
- neutrino decoupling: see decoupling
- neutrino detector (neutrino observatory): device to detect neutrinos
- Neutrino Ettore Majorana Observatory: see KM3NeT
- neutrino experiment: see neutrino observatory
- Neutrino Extended Submarine Telescope with Oceanographic Research: see KM3NeT
- neutrino family: see neutrino
- neutrino flavor: see neutrino
- neutrino hotspot: region of sky from which significant neutrinos have been detected
- Neutrino Mediterranean Observatory: see KM3NeT
- neutrino observatory: device to detect neutrinos
- neutrino oscillation: neutrinos regularly morph into another flavor
- neutrino point source: see neutrino hotspot
- neutrino species: see neutrino
- neutrino temperature
- neutrinoless beta decay (neutrinoless double beta decay): possible type of rare beta decay
- neutrinoless double beta decay: possible type of rare beta decay
- CUORE: experiment to sense neutrinoless double beta decay
- EXO: experiment to detect neutrinoless double beta decay in xenon
- Sudbury Neutrino Observatory: Canadian underground neutrino detector
- neutrinos
- neutron: type of baryon that is stable and has no electric charge
- neutron capture: combination of an atomic nucleus and a neutron
- neutron degeneracy pressure: see electron degeneracy
- neutron star: stellar remnant consisting entirely of solar masses of neutrons
- neutron degenerate matter: matter made up primarily of neutrons
- neutron degenerate matter: see electron degeneracy
- neutron drip: neutrons exiting from nuclei
- neutron emission: see radioactive decay
- neutron heavy: see neutron drip
- neutron lifetime: see neutron capture
- neutron matter (neutron degenerate matter): matter made up primarily of neutrons
- neutron poor: see neutron rich
- neutron rich: more than usual neutrons
- neutron scattering: scattering of neutrons by atomic nuclei
- neutron spectrograph: see neutron scattering
- neutron spectrometer: device determining the energy of received free neutrons
- neutron spectroscopy: see neutron scattering
- neutron star: stellar remnant consisting entirely of solar masses of neutrons
- neutron star binary: see binary neutron star
- Neutron Star Interior Composition Explorer (NICER): space X-ray mission specifically to view neutron stars
- neutron star kick: see core collapse supernova
- neutron star kick: see velocity kick
- neutron star matter (neutron degenerate matter): matter made up primarily of neutrons
- neutron star merger: two neutron stars meeting and forming one
- neutron star merger: see binary neutron star
- GW detection: observed gravitational wave signal recognizable as an astronomical event
- GW170817: 2017 gravitational wave detection from a neutron star merger
- standard siren: transient whose gravitational waves indicate a specific distance
- neutron stars
- neutron-rich NSE: see nuclear statistical equilibrium
- neutron-star black-hole merger: a neutron star falling into a black hole
- neutron-star/black-hole merger
- GW detection: observed gravitational wave signal recognizable as an astronomical event
- neutronization: an electron and proton combining to form a neutron
- neutronization burst: see neutronization
- neutrons from carbon-13: process by which neutrons are freed in the s process
- NeVe: see rare designator prefixes
- New: see Shapley-Ames Catalog
- New Catalogue of Suspected Variable Stars: catalog from latter half of 20th century catalog
- New Frontiers
- CAESAR: planned space mission to return a sample of a comet
- Dragonfly: Titan flying rover under development
- Enceladus Life Finder: mission to search for life on Saturn moon Enceladus
- Juno: mission to Jupiter
- New Horizons: explorer spaceship sent to Pluto
- OSIRIS-REx: space mission aiming to return a sample of an asteroid
- New Frontiers 1 (New Horizons): explorer spaceship sent to Pluto
- New Frontiers 2 (Juno): mission to Jupiter
- New Frontiers 3 (OSIRIS-REx): space mission aiming to return a sample of an asteroid
- New Frontiers 4 (Dragonfly): Titan flying rover under development
- New Frontiers Program
- NASA: includes space-based astronomy research
- New General Catalogue: 1888 catalog of galaxies, star clusters, and other nebulae
- New general catalogue of double stars within 120° of the North pole. (Aitken Double Star Catalogue): 1932 catalog with both multiple-star systems and non-orbiting double stars
- New General Catalogue of Nebulae and Clusters of Stars (New General Catalogue): 1888 catalog of galaxies, star clusters, and other nebulae
- New Gravitational Wave Observatory: past proposal for space mission to detect gravitational waves
- New Horizons: explorer spaceship sent to Pluto
- New Jersey
- CAPMAP: early 2000s array that surveyed CMB polarization
- New Luyten Two-Tenths Arcsecond Catalog: see Luyten Two-Tenths Arcsecond Catalog
- New Mexico
- New Mexico Skies
- new Moon
- earthshine: reflected and emitted electromagnetic radiation from Earth
- New Robotic Telescope: see Liverpool Telescope
- New Robotic Telescope: see Roque de los Muchachos Observatory
- New Solar Telescope: see Big Bear Solar Observatory
- New South Wales
- SkyMapper: automated 1.35 m optical telescope in Australia
- New Technology Telescope: 3.58-meter reflector telescope in Chile
- New Worlds Imager (New Worlds Mission): plan for space occulter to facilitate the view of exoplanets
- New Worlds Mission: plan for space occulter to facilitate the view of exoplanets
- New Worlds Observer (New Worlds Mission): plan for space occulter to facilitate the view of exoplanets
- New X-ray Telescope (Hitomi): 2016 Japanese space X-ray telescope
- New Zealand
- MOA: search for microlensing events
- NEWS: planned near-infrared spectrometer on Discovery Channel Telescope
- newton: see joule
- tesla: unit of magnetic flux density
- Newton's first law: see Newton's laws
- Newton's law of gravitation: see Newton's laws
- Newton's laws: physical laws of dynamics and gravitation
- Newton's laws of motion: see Newton's laws
- Newton's second law: see Newton's laws
- Newton's third law: see Newton's laws
- Newtonian gravitational constant (gravitational constant): indicates how much pull between two masses
- Newtonian gravitational field: see gravitational field
- Newtonian gravity: see Newton's laws
- Newtonian mechanics: see Newton's laws
- Newtonian telescope: type of reflector telescope
- nEXO: see EXO
- NeXT (Hitomi): 2016 Japanese space X-ray telescope
- Next Generation Space Telescope (James Webb Space Telescope): 6.5-meter infrared space telescope at L2
- Next Generation Very Large Array: planned radio telescope array as a follow-on to ALMA and the Jansky VLA
- next-EXO: see EXO
- Next-generation Transit Survey (NGTS): survey of transits from Chile
- NEXTSat: see Autonomous Space Transport Robotic Operations
- NF1 (New Horizons): explorer spaceship sent to Pluto
- NF2 (Juno): mission to Jupiter
- NF3 (OSIRIS-REx): space mission aiming to return a sample of an asteroid
- NF4 (Dragonfly): Titan flying rover under development
- NFI: see PUNCH
- nFLASH: see Atacama Pathfinder Experiment
- NFW profile (Navarro-Frenk-White profile): a dark matter spatial mass distribution function
- NG (non-Gaussian): something requiring adjustment from the Gaussian function
- NG: see NGTS
- NGC (New General Catalogue): 1888 catalog of galaxies, star clusters, and other nebulae
- NGC 104 (47 Tucanae): bright globular cluster
- NGC 1052: elliptical galaxy with ultra diffuse dwarf satellites
- NGC 1052 Group: see NGC 1052
- NGC 1052-DF2: see NGC 1052
- NGC 1052-DF4: see NGC 1052
- NGC 1064
- neutrino hotspot: region of sky from which significant neutrinos have been detected
- NGC 1068 (Messier 77): easily-observed spiral galaxy
- NGC 1275: see Perseus Cluster
- NGC 1344
- shell galaxy: galaxy with one or more surrounding layers of brightness
- NGC 147
- NGC 1555
- T Tauri: variable star taken as example of young star
- NGC 1600: elliptical galaxy with large supermassive black hole
- NGC 185
- NGC 1866: globular cluster of interest in the LMC
- NGC 1952 (Crab Nebula): supernova remnant in Taurus
- NGC 1976 (Orion Nebula): easily-observed nebula that includes SF regions
- NGC 2070
- NGC 224 (Andromeda): spiral galaxy in the Local Group
- NGC 2363: low-metallicity SF region
- NGC 2366: see NGC 2363
- NGC 253: spiral galaxy 11 million light-years away
- NGC 2682 (Messier 67): old open cluster in Cancer
- NGC 2736: see Vela supernova remnant
- NGC 2770: spiral galaxy that has shown a number of supernovae
- NGC 3031
- NGC 3034 (M82): nearby starburst galaxy
- NGC 3132: PN of interest in southern sky
- NGC 3201: globular cluster in which a black hole has been identified
- NGC 3314: a pair of galaxies aligned with us
- NGC 3372 (Carina Nebula): HII region with stars and nebulae of interest
- NGC 346: open cluster in SMC
- NGC 4258 (Messier 106): spiral galaxy with maser
- NGC 4321 (Messier 100): easily-observed spiral galaxy
- NGC 4374 (Messier 84): elliptical galaxy with jets
- NGC 4486 (M87): supergiant elliptical galaxy in local universe
- NGC 4594 (Sombrero Galaxy): striking spiral galaxy with very large bulge
- NGC 4736
- NGC 4826 (M64): nearby dusty galaxy
- NGC 4945
- NGC 4993: see GW170817
- NGC 5128 (Centaurus A): nearby radio galaxy
- NGC 5139 (Omega Centauri): large globular cluster
- NGC 5194 (Whirlpool Galaxy): easily-observed spiral galaxy
- NGC 5236
- NGC 5457 (Pinwheel Galaxy): easily-observed spiral galaxy
- NGC 5548
- NGC 5866 (Spindle Galaxy): disk galaxy for which we have an edge-on view
- NGC 598 (Triangulum Galaxy): small spiral galaxy in the Local Group
- NGC 628 (Messier 74): easily-observed spiral galaxy
- NGC 6822
- NGC 6946: face-on spiral galaxy
- NGC 6960: see Cygnus Loop
- NGC 6992: see Cygnus Loop
- NGC 6995: see Cygnus Loop
- NGC 7078 (Messier 15): globular cluster with collapsed core
- NGC 7317: see Stephan's Quintet
- NGC 7318A: see Stephan's Quintet
- NGC 7318B: see Stephan's Quintet
- NGC 7319: see Stephan's Quintet
- NGC 7320: see Stephan's Quintet
- NGC 7331: spiral galaxy without a bar
- NGC 7469: spiral galaxy with AGN outflow
- NGC 7727: irregular galaxy with two SMBHs
- NGC2000.0: see New General Catalogue
- NGCFHT: see Canada-France-Hawaii Telescope
- ngEHT: see Event Horizon Telescope
- NGIMS: see MAVEN
- NGO (New Gravitational Wave Observatory): past proposal for space mission to detect gravitational waves
- NGPS: see Hale Telescope
- NGS: see Galaxy Evolution Explorer
- NGS: see guide star
- NGS-POSS (Palomar Observatory Sky Survey): 1950s photographic plates from Palomar 48 inch telescope
- NGST (James Webb Space Telescope): 6.5-meter infrared space telescope at L2
- NGTS: survey of transits from Chile
- ngVLA (Next Generation Very Large Array): planned radio telescope array as a follow-on to ALMA and the Jansky VLA
- NH: see rare designator prefixes
- NH3 (ammonia): particular compound of nitrogen and hydrogen
- NHI: see particle number
- NHICAT: see HIPASS
- NHO (Roque de los Muchachos Observatory): observatory at La Palma in the Canary Islands
- NI
- Ni (nickel): metal, Ni, atomic number 28
- Nice model: model of the evolution of the solar system
- NICER: space X-ray mission specifically to view neutron stars
- Nicholas U. Mayall Telescope (Mayall 4m Telescope): 4 meter reflector telescope at Kitt Peak
- NICI: see Gemini Observatory
- nickel: metal, Ni, atomic number 28
- r-process: synthesis of elements through neutron capture faster than beta decay
- nickel-56: see nickel
- nickel-58: see nickel
- nickel-62: see nickel
- NICMOS: see Hubble Space Telescope
- NICMOS3
- NICS: see Telescopio Nazionale Galileo
- NIFS: see Gemini Observatory
- night sky
- light pollution: light from cities that interferes with astronomical observation
- visible light: electromagnetic radiation that our eyes can sense
- nightglow (airglow): glow from a planet's atmosphere
- NIHTS: see Lowell Discovery Telescope
- NII
- NIII
- NIKA: see IRAM 30m Telescope
- NIKA2: see IRAM 30m Telescope
- Nili Fossae: region of grabens on Mars
- NIMS: see Galileo
- NIR (near infrared): electromagnetic radiation in the range of 750-2500 nm
- NIR: see Southern African Large Telescope
- NIR3: see Hayabusa2
- NIRC: see Keck Observatory
- NIRC-2: see Keck Observatory
- NIRC2
- PALMS: survey to find exoplanets for direct imaging
- NIRCam: near infrared imager on JWST
- NIRCam: see James Webb Space Telescope
- grism: combination of a grating and a prism
- NIRES: see Keck Observatory
- NIRI: see Gemini Observatory
- NIRIS: see Big Bear Solar Observatory
- NIRISS: see James Webb Space Telescope
- NIRISS SOSS: see James Webb Space Telescope
- NIRPS: near-infrared extension to HARPS spectrograph
- NIRPS: see ESO 3.6m Telescope
- NIRSPEC: see Keck Observatory
- NIRSpec: near infrared spectrograph on JWST
- NIRSpec: see James Webb Space Telescope
- NIRSpec G395: see James Webb Space Telescope
- NIRWALS: see Southern African Large Telescope
- NIS: see NEAR Shoemaker
- NISP: see Euclid
- NIST (National Institute of Standards and Technology): US agency defining standards
- NISTAR: see DISCOVR
- nitrite: ion of a nitrogen atom and two oxygen atoms with extra electron
- nitrite salt
- nitrite: ion of a nitrogen atom and two oxygen atoms with extra electron
- nitrogen: metal, N, atomic number 7
- amine: type of compound containing nitrogen
- ammonia: particular compound of nitrogen and hydrogen
- hydrogen cyanide: compound of hydrogen, carbon, and nitrogen, one atom each
- nitrite: ion of a nitrogen atom and two oxygen atoms with extra electron
- nitrogen dioxide
- nitrite: ion of a nitrogen atom and two oxygen atoms with extra electron
- nitrogen-enhanced metal-poor star: see carbon star
- nitrogen-rich Wolf-Rayet: see Wolf-Rayet star
- NIVR
- IRAS: 1983 satellite that surveyed the sky in infrared
- Nix: see Pluto
- NLAGN: see active galactic nucleus
- NLR (narrow line region): AGN region producing narrower lines
- NLR: see NEAR Shoemaker
- NLRG: see radio galaxy
- NLTE: see local thermodynamic equilibrium
- NLTT: see Luyten Two-Tenths Arcsecond Catalog
- nm
- NML: see rare designator prefixes
- NMS: see Giotto
- NN (neural network): computer program structure inspired by the brain
- NN-EXPLORE
- no-hair theorem: proposition that a black hole only has mass, rotation, and charge
- No-U Turn Sampler: see PyMC
- NO2
- nitrite: ion of a nitrogen atom and two oxygen atoms with extra electron
- NO2- (nitrite): ion of a nitrogen atom and two oxygen atoms with extra electron
- NOAA (National Oceanic and Atmospheric Administration): US meteorology and oceanography agency
- MarsWRF: Mars-oriented general circulation model
- SWFO-L1: future NOAA space-weather warning satellite
- NOAO (National Optical Astronomy Observatory): previous name of US optical astronomy organization
- NOAO Deep Wide-field Survey: survey investigating large scale structure of the universe
- NOAO Deep-Wide-Field Survey
- NOAO Source Catalog: catalog compiled from NOAO public data
- noble gas
- nodding: see chopping mirror
- NODO (NASA Orbital Debris Observatory): 1990s telescope aimed at tracking space junk
- NOEMA (Northern Extended Millimeter Array): large radio telescope array under construction in Europe
- PHIBSS: survey of CO in distant galaxies
- NOFS: see USNO
- NOIRLab: US optical/infrared astronomy organization
- noise
- noise power
- noise temperature: a measure of noise in electronic devices
- noise-equivalent power: signal power that equals the noise
- NOMAD: astrometric star catalog
- NOMAD: see Trace Gas Orbiter
- NOMAD1: see NOMAD
- NOMIC: see Large Binocular Telescope
- non chemical equilibrium: see chemical equilibrium
- non local thermodynamic equilibrium: see local thermodynamic equilibrium
- non-baryonic matter: see baryonic matter
- baryon: protons, neutrons, and other three-quark particles
- dark matter: matter in galaxies and galaxy clusters suggested by their gravity
- non-carbonaceous chondrite: see carbonaceous chondrite
- non-CE: see chemical equilibrium
- non-condensing gas: see biosignature
- non-Gaussian: something requiring adjustment from the Gaussian function
- non-Gaussianity: see non-Gaussian
- non-inertial reference frame: see inertial reference frame
- non-integrated Sachs-Wolfe effect: see Sachs-Wolfe effect
- non-LTE: see local thermodynamic equilibrium
- CMFGEN: RT code designed to handle significant stellar wind
- non-metal
- helium: non-metallic element, He, atomic number 2
- hydrogen: most prominent element, atomic number 1
- non-Planckian: see black-body radiation
- non-Planckian: see thermal emission
- non-relativistic speed: see relativistic speed
- non-relativistic speed: see relativity
- non-standard cosmologies (alternative cosmologies): cosmological models other than Big Bang/Lambda-CDM
- non-thermal: regarding radiation other than black-body
- non-thermal emission: EMR not due to a body's heat
- non-thermal escape: see atmospheric escape
- non-thermal radiation (non-thermal emission): EMR not due to a body's heat
- nonbaryonic matter: see baryonic matter
- baryon: protons, neutrons, and other three-quark particles
- noncollisional: see stellar dynamics
- nondimensionalization: manipulation of an equation to remove units
- nonlinear GW memory: see gravitational-wave memory
- nonparametric model: model developed avoiding assumptions regarding a basic structure
- nonparametric statistics: see nonparametric model
- nonsingular black hole model: see black hole model
- Nordic Optical Telescope: see Roque de los Muchachos Observatory
- Norma Arm: see spiral arm
- Norma Cluster
- ESO 137-001: barred spiral galaxy in the Abell 3627 cluster
- Norma-Cygnus Arm: see spiral arm
- normal color index: see color index
- normal distribution: see Gaussian function
- normal elastic thickness: see elastic thickness
- normal mode: resonant surface waves in seismology
- normal mode (eigenmode): vibration mode of an oscillator where all parts move at the same frequency
- normalization constant: see probability density function
- normalization constant: see probability mass function
- normalized PDF: see probability density function
- normalized PMF: see probability mass function
- normalizing constant: see probability density function
- normalizing constant: see probability mass function
- Norsk Astronomisk Selskap: Norwegian non-profit association of astronomers
- North American Meteor Network: former group of amateurs with an interest in meteors
- North American Nanohertz Observatory for Gravitational Waves (NANOGrav): effort to detect gravitational waves through pulsar timing
- North American Small Telescope Cooperative (International Small Telescope Cooperative): former cooperative of small research telescopes
- north galactic pole (galactic north): determination of the more northern direction of the Milky Way's axis
- north node: see orbital element
- north polar sequence: set of stars previously used to define magnitudes
- Northern Cross Radio Telescope
- Northern Extended Millimeter Array: large radio telescope array under construction in Europe
- PHIBSS: survey of CO in distant galaxies
- Northern Hemisphere Observatory (Roque de los Muchachos Observatory): observatory at La Palma in the Canary Islands
- northern lights: see aurora
- northern zone of avoidance: see zone of avoidance
- Norway
- Norwegian Astronomical Society (Norsk Astronomisk Selskap): Norwegian non-profit association of astronomers
- NOT: see Roque de los Muchachos Observatory
- Nova: see nova
- nova: white dwarf explosion
- Nova Delphini 2013 (V339 Delphini): 2013 nova showing lithium synthesis
- nova eruption: see nova
- nova remnant: see supernova remnant
- NP: see black-body radiation
- NP: see thermal emission
- NPDF: see probability density function
- NPM1G: see rare designator prefixes
- NPOI (Navy Precision Optical Interferometer): optical interferometer in Arizona
- NPS (north polar sequence): set of stars previously used to define magnitudes
- NR (numerical relativity): solving GR-sensitive problems with numerical methods
- NRAL (Jodrell Bank Observatory): radio observatory in England
- NRAO (NRAO Catalog): 1960s follow-up to Cambridge radio surveys
- NRAO (National Radio Astronomy Observatory): US radio astronomy organization
- NRAO Catalog: 1960s follow-up to Cambridge radio surveys
- NRAO Seven-beam Receiver
- NRAO VLA Sky Survey: 1990s microwave survey of 82% of the sky
- NRES: see Las Cumbres Observatory
- NRL (Naval Research Laboratory): US Navy scientific research arm
- NRL White-light Coronagraph: see OSO 7
- NRQZ: see Green Bank Observatory
- dark sky: sky with limited light pollution
- NRT (Nançay Radio Telescope): large radio telescope in France
- NRT: see Liverpool Telescope
- NRT: see Roque de los Muchachos Observatory
- NS (neutron star): stellar remnant consisting entirely of solar masses of neutrons
- NS: see Lunar Prospector
- NS: see MESSENGER
- NS: see rare designator prefixes
- NS equations (Navier-Stokes equations): equations that describe fluid dynamics
- NS kick: see core collapse supernova
- NS kick: see velocity kick
- NS merger (neutron star merger): two neutron stars meeting and forming one
- standard siren: transient whose gravitational waves indicate a specific distance
- NSB: see binary neutron star
- NSBH merger (neutron-star black-hole merger): a neutron star falling into a black hole
- NSBM (NASA Standard Breakup Model): model maintained by NASA of how satellites fragment
- NSC (NOAO Source Catalog): catalog compiled from NOAO public data
- NSC: see stellar nucleus
- NSE (nuclear statistical equilibrium): equilibrium of nuclei emitting and absorbing particles
- NSF (National Science Foundation): US government organization funding scientific research
- NSF AST: US government astronomical research funding division
- NSF AST MSIP: see NSF AST
- NSF Astronomical Sciences Division (NSF AST): US government astronomical research funding division
- NSFCam2: see IRTF
- NSII (Narrabri Stellar Intensity Interferometer): 1960s optical interferometer for measuring stellar diameters
- NSNF (Nearby Supernova Factory): survey that scanned transient data for supernovae
- NSO (National Solar Observatory): US government sponsored solar observatory
- NSSDC (NASA Space Science Data Coordinated Archive): NASA archive of flight information and astronomy findings
- NSSDCA (NASA Space Science Data Coordinated Archive): NASA archive of flight information and astronomy findings
- NST: see Big Bear Solar Observatory
- NSV (New Catalogue of Suspected Variable Stars): catalog from latter half of 20th century catalog
- NSV Release 2: see New Catalogue of Suspected Variable Stars
- NSVS: see ROTSE
- NT (non-thermal): regarding radiation other than black-body
- NTT (New Technology Telescope): 3.58-meter reflector telescope in Chile
- NTTS: see T-Tauri star
- NTTS: see rare designator prefixes
- nuclear
- nuclear binding energy: see binding energy
- nuclear cluster (stellar nucleus): group of many stars at the center of a galaxy
- nuclear drip line: see neutron drip
- nuclear energy generation rate: fusion power per unit mass
- nuclear fission: see fusion
- nuclear fusion (fusion): formation of an atomic nucleus nuclei from multiple smaller nuclei
- nuclear isomer: see nuclide
- metastable: characteristic of an excited state that lasts longer than typical
- nuclear photodissociation
- nuclear reaction: see nuclear energy generation rate
- fusion: formation of an atomic nucleus nuclei from multiple smaller nuclei
- nuclear reaction rate: see nuclear energy generation rate
- nuclear species (nuclide): atomic nucleus associated with a specific isotope
- Nuclear Spectroscopic Telescope Array (NuSTAR): space telescope for high-energy X-rays
- nuclear star cluster (stellar nucleus): group of many stars at the center of a galaxy
- nuclear star cluster: see stellar nucleus
- nuclear statistical equilibrium: equilibrium of nuclei emitting and absorbing particles
- nuclear symmetry energy: see valley of beta stability
- nuclear timescale: see timescale
- nucleon: proton or neutron
- dalton: mass unit used on atomic scale
- element: class of atom based on its number of protons
- fusion: formation of an atomic nucleus nuclei from multiple smaller nuclei
- isotope: subclass of an element with a specific number of nucleons
- standard model: model of elementary particles including quarks
- nucleon number (mass number): number of nucleons in an atomic nucleus
- nucleosynthesis: creation of atomic nuclei
- nucleotides
- Lego principle: principle that life is associated with a skew in molecule abundances
- nucleus: see comet
- nucleus notation
- isotope: subclass of an element with a specific number of nucleons
- nuclide: atomic nucleus associated with a specific isotope
- Nuffield Radio Astronomy Laboratory (Jodrell Bank Observatory): radio observatory in England
- null corrector: instrument for testing mirrors
- null hypothesis
- null test: see null corrector
- nulling: see speckle suppression
- number density: number of objects per volume
- numbered object: see minor planet
- numbered object: see provisional designation
- numerical analysis: the study and use of numerical methods of solving equations
- numerical integration: see Markov chain Monte Carlo
- numerical integration: see numerical methods
- numerical methods: using equations through repetitive arithmetic
- numerical analysis: the study and use of numerical methods of solving equations
- stencil: pattern of input to numerical solutions at a point
- numerical model: see numerical methods
- numerical relativity: solving GR-sensitive problems with numerical methods
- numerical weather prediction: Earth weather prediction by computer equation-solving and/or simulation
- numerical weather prediction model: see numerical weather prediction
- NumPy: Python library for numerical programming with arrays
- NumPy: see PyMC
- NuSTAR: space telescope for high-energy X-rays
- StrayCats: survey of X-ray sources detectable in NuSTAR stray light
- NUT parameter: see Taub-NUT spacetime
- nutation: precession of a body's axis of rotation
- Chandler wobble: shifting of the Earth's axis of rotation relative to the Earth itself
- NUTS: see PyMC
- NUV: see ultraviolet
- ULTRASAT: future satellite to detect UV transients
- NVSS (NRAO VLA Sky Survey): 1990s microwave survey of 82% of the sky
- NWO (Nederlandse Organisatie voor Wetenschappelijk Onderzoek): Dutch research council
- ASTRON: Netherlands radio astronomy research organization
- Astronet: European astronomy consortium
- NWP (numerical weather prediction): Earth weather prediction by computer equation-solving and/or simulation
- NWP model: see numerical weather prediction
- Nysa
- NZO: see double star designation
Index