Comments: Seeing was bad with C8 (20 cm) aperture, so i changed to prepared smaller Mak 127/1500.

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Observation 1
Feature(s)	GRS blue festoons white rifts white plumes Callisto
Filter(s)	l
Date	2023-12-17 20:17:00
Julian day	2460296.345138889
System I	234.7475°
System II	38.399067°
System III	87.82385°
Illumination	99.4%
Phase angle	8.600000381469727°
Solar longitude	123.9°
Eq. diameter	46.01″
Derotation	10.0 min