Calculation Tools


Apparent Size of Some Common Celestial Objects

Object NameApproximate Apparent Size
Mars20 arc-seconds (at opposition)
Jupiter40 arc-seconds (at opposition)
Ring Nebula (M57)1.4x1.0 arc-minutes
Dumbbell Nebula (M27)8.0x6.0 arc-minutes
Hercules Cluster (M13)15 arc-minutes in diameter
Wild Duck Cluster (M11)14.0x14.0 arc-minutes
Moon/Sun30 arc-minutes in diameter
Orion Nebula (M42)80x60 arc-minutes
Andromeda Galaxy (M31)190x60 arc-minutes