(direction coordinate above/below celestial equator)
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
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.
Referenced by pages:
AD Leonis (AD Leo)
Algol (Beta Per)
AU Microscopii (AU Mic)
Canis Major Dwarf Galaxy
Circinus Galaxy (ESO 97-G13)
Extended Groth Strip (EGS)
Epsilon Indi (ε Indi)
equatorial coordinate system
Galactic All-sky Survey (GASS)
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)
Hubble Ultra-Deep Field (HUDF)
LHS 3844 b
Large Magellanic Cloud (LMC)
Crab Nebula (M1)
Triangulum Galaxy (M33)
NRAO VLA Sky Survey (NVSS)
Hulse-Taylor Binary (PSR B1913+16)
Rho Ophiuchi Cloud Complex
right ascension (RA)
Sagittarius Dwarf Irregular Galaxy (SagDIG)
Sagittarius Dwarf Elliptical Galaxy (Sgr dE)
Small Magellanic Cloud (SMC)
Taurus Molecular Cloud 1 (TMC-1)
TOI 700 d
TW Hydrae (TW Hya)
Ursa Major II Dwarf
zone of avoidance (ZOA)