Astronomical Dictionary Page #1

Culmination

A general term for the hightest and lowest points a planet or celestial body reaches in the sky rela...

Culmination

A general term for the hightest and lowest points a planet or celestial body reaches in the sky rela...

Declination

Distance along the hour circle between the celestial equator and a celestial body measured in degree...

Descending Node

Also called the south node, the point in the orbit of an object, when it crosses the ecliptic whilst...

Direct Motion

1 Rotation or orbital motion in an anticlockwise direction when viewed from the north pole of the Su...

Dwarf Star

A star, which lies on the main sequence and is too small to be classified as a giant star or a super...

Eccentricity

Literally, not circular. The eccentricity of an ellipse (orbit) is the ratio of the distance between...

Eclipse

A chance alignment between the Sun, or any other celestial object, and two other celestial objects i...

Ecliptic

The great circle formed by the intersection of the plane of the Ecliptic with the Celestial Sph...

Elongation

The angular distance of an interior planet from the Sun, as seen from the Earth. The term Greatest E...

Equatorial Mount

A telescope mount so designed so that the two axes, which support it, are aligned, one to the polar ...

Equinox

Literally, the time of equal day and night. This is the time when the Sun crosses the celestial equa...

Facula

Large, irregular, bright areas on the surface of the Sun, particularly near the limb. They precede t...

Filament

A strand of (relatively) cool gas suspended over the Sun (or star) by magnetic fields, which appears...

Galaxy

Vast star systems containing thousands of billions of stars, dust and gas, held together by gravity....

Galilean Moons

Jupiter's four largest moons: Io, Europa, Ganymede and Callisto. ...

Galileo

(1564-1642) Italian mathematician, astronomer, and physicist. First to use a telescope to observe th...

Geosynchronous Orbit

Sometimes known as a geostationary orbit, in which a satellite's orbital velocity is matched to the ...

Globular Cluster

A spherical cluster of older stars, often found in galaxies. These clusters form a sphere surroundin...

Fortuna

In Roman mythology, goddess of fortune, chance and luck....

feldspar

A group of rock-forming minerals that make up about 60% of the Earth's crust....

Fault

A fracture or zone of fractures in a planet's crust, accompanied by displacement of the opposing sid...

Europa

In Greek mythology, a mistress of Zeus to whom he appeared as a gentle white heifer. Zeus persuaded ...

Escarpment

A long, more or less continuous cliff or relatively steep slope facing in one general direction, pro...

Encke

Johann Franz Encke (1791-1865) German astronomer at the Seeberg Observatory, Switzerland. Determined...