Term
|
Definition
| An imaginary line in the celestial sphere that goes from the north celestial pole through the zenith to the south celestial pole. The north-south line directly overhead. |
|
|
Term
|
Definition
| The height, in degrees, of a star's position around the horizon clockwise from due north. A star due east has this of 90 degrees. This number changes as the star rises and sets. |
|
|
Term
|
Definition
| The point in the sky directly above the observer. |
|
|
Term
|
Definition
| The height, in degrees, of a star's position along a line running from the horizon to the zenith. The coordinates of a star can be given in Azimuth and this. These numbers will change as the sun rises and sets. |
|
|
Term
|
Definition
| The celestial meridian that is overhead at noon on the first day of autumn. Stars on the this have a right ascension of 12 hours. |
|
|
Term
|
Definition
| An imaginary, transparent sphere with Earth at it's center. All stars are pictured as being in this sphere. This is what the star globe is. |
|
|
Term
|
Definition
| The axis around which the celestial sphere rotates. As the Earth rotates, the stars appear to circle this. |
|
|
Term
|
Definition
| The imaginary line on the celestial sphere directly above the Earth's equator halfway between the north and south poles. |
|
|
Term
|
Definition
| The angle, in degrees, of a star's position above or below the celestial equator. Is negative when below the celestial equator. When on the celestial equator, a star has this of 0 degrees. A star at the north celestial pole has this of 90 degrees. |
|
|
Term
|
Definition
| The plane of the Earth's orbit around the sun. On a star map or star glove, the apparent path of the sun across the celestial sphere. |
|
|
Term
|
Definition
| The imaginary line around the center of the Earth halfway between North and South poles. |
|
|
Term
|
Definition
| The angle, in degrees, of a position on Earth above the equator. Is negative when below the equator. |
|
|
Term
|
Definition
| The angle, in degrees, of a position on Earth around the equator from the Greenwich Meridian. |
|
|
Term
|
Definition
| The angle, in hours, of a star's position around the celestial equator with respect to the Vernal Equinoctal. |
|
|
Term
| Sidreal Day and Sidreal Time |
|
Definition
| The day and time measured with respect to the stars. |
|
|
Term
|
Definition
| The day and time measured with respect to the sun. |
|
|
Term
|
Definition
| The solar time at a longitude of 0 degrees. Often called Greenwich Mean time, because the British Royal Observatory in Greenwich sits on 0 degrees longitude. |
|
|
Term
| Vernal Equinocta(Spring Equinoctal) |
|
Definition
| The celestial meridian that is overhead at noon on the first day of spring. Stars on the have a right ascension of 0 hours. |
|
|
