What is an orbital epoch?

Orbit Epoch. The orbit Epoch indicates the time at which the satellite’s position, orbit orientation and orbit shape were last known. Knowing a satellite’s position and orbit orientation alone is not enough if you want to know the satellite’s future position.

What are RA and DEC?

R.A. means “right ascension” and Dec. means “declination”; these are the two parts of the equatorial coordinate system. Astronomers developed it to correspond to longitude and latitude on Earth.

What are J2000 coordinates?

Therefore, a complete specification of the coordinates for an astronomical object requires both the date of the equinox and of the epoch. The currently used standard equinox and epoch is J2000. 0, which is January 1, 2000 at 12:00 TT. The prefix “J” indicates that it is a Julian epoch.

What is the right ascension of the Meridian?

Right ascension is the celestial equivalent of terrestrial longitude. The line which passes through the highest point in the sky, called the meridian, is the projection of a longitude line onto the celestial sphere.

Where does the eccentricity vector point?

In celestial mechanics, the eccentricity vector of a Kepler orbit is the dimensionless vector with direction pointing from apoapsis to periapsis and with magnitude equal to the orbit’s scalar eccentricity. For Kepler orbits the eccentricity vector is a constant of motion.

What is Omega orbit?

Argument of periapsis (ω) defines the orientation of the ellipse in the orbital plane, as an angle measured from the ascending node to the periapsis (the closest point the satellite object comes to the primary object around which it orbits, the blue angle ω in the diagram).

What is telescope RA?

RA (right ascension) and Dec (declination) are the coordinates on the sky that correspond to longitude and latitude on Earth. RA measures east and west on the celestial sphere and is like longitude on the Earth. Dec measures north and south on the celestial sphere and is like latitude on the Earth.

What is Alt and Az?

Altitude (alt.), sometimes referred to as elevation (el.), is the angle between the object and the observer’s local horizon. For visible objects, it is an angle between 0° and 90°. Azimuth (az.) is the angle of the object around the horizon, usually measured from true north and increasing eastward.

What is equatorial grid?

The equatorial coordinate system is basically the projection of the latitude and longitude coordinate system we use here on Earth, onto the celestial sphere.

What is the DEC of the celestial equator?

0° DEC
Declination (DEC) is the celestial sphere’s equivalent of latitude and it is expressed in degrees, as is latitude. For DEC, + and – refer to north and south, respectively. The celestial equator is 0° DEC, and the poles are +90° and -90°.

What latitude is the equator at?

0 degrees
Latitude lines are labeled from the north pole (90 degrees north) to the equator (0 degrees) and down to the south pole (90 degrees south).

What is oblique ascension?

(Astron.) an arc of the equator, intercepted between the first point of Aries and that point of the equator which rises together with a star, in an oblique sphere; or the arc of the equator intercepted between the first point of Aries and that point of the equator that comes to the horizon with a star.