Callisto
Callisto
Moon
Gemini
Visible
Level 3
Medium telescope (6-8") - Timing dependent
Properties
Magnitude
5.7
Angular Size
1.5 arcmin
Type: Moon
Distance: 0.013 AU
Orbital Period: 16.7 days
Diameter: 2,410 km
Atmosphere: Thin carbon dioxide
Features: Craters, valhalla
Heavily cratered surface.
Position & Identifiers
RA
07h 05m 53.6s
Dec
+22° 56' 44.9"
Constellation
Gemini
Catalog
Callisto
Physical Properties
Diameter
2,410 km
(0.19× Earth)
Mass
1.08e23 kg
Albedo
0.19
(19% reflected)
Temperature
-193°C to -139°C
Rotation
16.7 days
Atmosphere
Thin carbon dioxide
Surface
Craters, valhalla
Angular Size
0.7″ (current)
Orbital Properties
Semi-major Axis
0.0126 AU
(1,881,941 km)
Eccentricity
0.0070
Inclination
0.30°
Orbital Period
16.7 days
Distance
4.991 AU
(41.5 light-min)
Elongation
98.9°
Good
Observing Tips
Best Months
May
, June
, July
Visibility
Binoculars
Where to Look
Near Jupiter
Notes
Heavily cratered surface.
Parent Body
Discovery
Discovered by
Galileo Galilei
Date
1610
Current Ephemeris
4.991
AU from Earth
746.7M
km
0.7″
Angular Size
99°
Elongation
Visibility
Set a location in User Settings to see visibility data.
Community Photos (1)
Credit: zelario12. License: CC BY-SA 2.0. (Wikimedia Commons)
Skybred Feb 28, 2026