[Add observation]

Observation 1
Feature(s)	GRS Io Ganymede
Filter(s)	r
Date	2017-05-02 22:00:58
Julian day	2457876.4166666665
System I	339.23°
System II	246.93°
System III	12.68°
Illumination	100.0%
Phase angle	4.699999809265137°
Solar longitude	279.6°
Eq. diameter	43.42″
Derotation	0.0 min