Astrophysics (Index)About

declination

(dec)
(direction coordinate above/below celestial equator)

Declination is a coordinate for a point in the sky consisting of the angle to it measured from the nearest point on the celestial equator (the plane through the Earth's equator). It and right ascension together specify a direction, i.e., a point in the celestial sphere. Declination and right ascension are analogous to latitude and longitude, respectively.

Declination is measured in degrees within the range of +90° to -90°, with +90° corresponding to north along the direction of the Earth's axis. The North star is approximately along the line of this axis and has a declination just above 89°. The celestial equator is 0° declination. The constellation Orion spans the plane of the celestial equator, so some points in the region assigned to Orion have a declination of 0°. A positive declination indicates the northern hemisphere, i.e., the spots on Earth that the point on the celestial sphere passes directly over are in the Earth's northern hemisphere. Analogously, points directly above southern hemisphere sites have a negative declination.


The word declination is used (outside astronomy) in the use of compasses for navigation on Earth, indicating the angle distance between north and magnetic north, an angle which varies over the surface of the Earth.


(coordinate,equatorial,celestial sphere,measure)
Further reading:
http://en.wikipedia.org/wiki/Declination
http://curious.astro.cornell.edu/ask-a-question/112-observational-astronomy/stargazing/technical-questions/699-what-are-ra-and-dec-intermediate

Referenced by pages:
Achernar
AD Leonis (AD Leo)
Algol (Beta Per)
Alpha Centauri
Arcturus
AU Microscopii (AU Mic)
Baade's Window
Barnard's Star
Beta Centauri
Betelgeuse
Canis Major Dwarf Galaxy
Canopus
celestial equator
celestial sphere
Circinus Galaxy (ESO 97-G13)
COSMOSOMAS
DSA-2000
Extended Groth Strip (EGS)
Elias 2-27
Epsilon Eridani
Epsilon Indi (ε Indi)
equatorial coordinate system
ESO 137-001
G239-25
galactic north
Galactic All-sky Survey (GASS)
GG Tau
Gliese 436 b (GJ 436 b)
HD 189733 b
HD 209458 b
Hubble Deep Field (HDF)
Hubble Deep Field South (HDF-S)
Herz catalog (Herz)
HL Tau
HR 8799
Hubble Ultra-Deep Field (HUDF)
J1407
J2000.0 equinox
J designator
Kapteyn's Star
Kepler Telescope
Lacaille 9352
Lalande 21185
LHS 1140
LHS 3844 b
Large Magellanic Cloud (LMC)
Lockman hole
Luhman 16
Luyten 726-8
Crab Nebula (M1)
Andromeda (M31)
Triangulum Galaxy (M33)
M64
M82
M87
NGC 1600
NGC 253
NGC 2770
NGC 3314
NRAO VLA Sky Survey (NVSS)
Procyon
Hulse-Taylor Binary (PSR B1913+16)
Rho Ophiuchi Cloud Complex
Rigel
right ascension (RA)
Ross 154
Ross 248
Sagittarius Dwarf Irregular Galaxy (SagDIG)
Sagittarius Dwarf Elliptical Galaxy (Sgr dE)
Scholz's Star
Sirius
Small Magellanic Cloud (SMC)
solar apex
Teegarden's Star
3C 273
3C 295
3C 48
Taurus Molecular Cloud 1 (TMC-1)
TOI 700 d
TRAPPIST-1
T Tauri
TW Hydrae (TW Hya)
Ursa Major II Dwarf
Vega
WISE 0855-0714
WISE 1506+7027
Wolf 359
zone of avoidance (ZOA)

Index