Rhea
Rhea
Moon
Pisces
Visible
Level 5
Expert level - Timing dependent
Properties
Magnitude
9.7
Angular Size
0.3 arcmin
Type: Moon
Distance: 0.004 AU
Orbital Period: 4.5 days
Diameter: 1,528 km
Atmosphere: Thin oxygen and carbon dioxide
Features: Craters, wispy terrain
Second largest moon of Saturn; icy surface with heavy cratering. Visible in 3-4 inch telescopes.
Position & Identifiers
RA
00h 21m 13.3s
Dec
-00° 01' 55.4"
Constellation
Pisces
Catalog
Rhea
Physical Properties
Diameter
1,528 km
(0.12× Earth)
Mass
2.31e21 kg
Albedo
0.65
(65% reflected)
Temperature
-220°C to -174°C
Rotation
4.5 days
Atmosphere
Thin oxygen and carbon dioxide
Surface
Craters, wispy terrain
Angular Size
0.2″ (current)
Orbital Properties
Semi-major Axis
0.0035 AU
(527,033 km)
Eccentricity
0.0010
Inclination
0.35°
Orbital Period
4.5 days
Distance
10.517 AU
(1.46 light-hours)
Elongation
2.4°
Near Sun
Observing Tips
Best Months
April
, May
, June
Visibility
Telescope
Where to Look
Near Saturn
Notes
Second largest moon of Saturn; icy surface with heavy cratering. Visible in 3-4 inch telescopes.
Parent Body
Discovery
Discovered by
Giovanni Cassini
Date
1672-12-23
Current Ephemeris
10.517
AU from Earth
1.57B
km
0.2″
Angular Size
2°
Elongation
Visibility
Set a location in User Settings to see visibility data.
Community Photos (1)
Credit: NASA/JPL/Space Science Institute. License: Public domain. (Wikimedia Commons)
Skybred Feb 28, 2026