Geocentric coordinates: the 3D vector from the center of the Earth to the center of the body. The components are in expressed in AU and are oriented with respect to the J2000 equatorial plane.
The distance between the center of the Earth and the center of the body in AU.
Heliocentric coordinates: The 3D vector from the center of the Sun to the center of the body.
Like gc, hc is expressed in AU and oriented with respect
to the J2000 equatorial plane.
The distance between the center of the Sun and the center of the body in astronomical units (AU).
The apparent visual magnitude of the celestial body.
The angle in degrees as seen from the center of the celestial body between the Sun and the Earth.
The value is always in the range 0 to 180.
The phase angle provides a measure of what fraction of the body's face appears
illuminated by the Sun as seen from the Earth.
When the observed body is the Sun, the phase property is set to 0,
although this has no physical meaning because the Sun emits, rather than reflects, light.
When the phase is near 0 degrees, the body appears "full".
When it is 90 degrees, the body appears "half full".
And when it is 180 degrees, the body appears "new" and is very difficult to see
because it is both dim and lost in the Sun's glare as seen from the Earth.
The fraction of the body's face that is illuminated by the Sun, as seen from the Earth.
Calculated from phase_angle for convenience.
This value ranges from 0 to 1.
Optionalring_For Saturn, this is the angular tilt of the planet's rings in degrees away
from the line of sight from the Earth. When the value is near 0, the rings
appear edge-on from the Earth and are therefore difficult to see.
When ring_tilt approaches its maximum value (about 27 degrees),
the rings appear widest and brightest from the Earth.
Unlike the JPL Horizons online tool,
this library includes the effect of the ring tilt angle in the calculated value
for Saturn's visual magnitude.
For all bodies other than Saturn, the value of ring_tilt is undefined.
The date and time pertaining to the other calculated values in this object.
Information about the apparent brightness and sunlit phase of a celestial object.