M38
Starfish Cluster
Properties
Position & Identifiers
Visibility
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About M38
Description
M38 is a large open cluster in Auriga, about 4,200 light-years from Earth. It contains roughly 100 stars spread across about 25 light-years, with an age of approximately 220 million years. The cluster's brighter stars form a distinctive cross or X-shaped pattern. The smaller cluster NGC 1907 lies just 30 arcminutes to the south.
Observing Tips
Located about 2.5 degrees northwest of M36, completing the Auriga trio. Binoculars show a large, diffuse hazy patch. A telescope at 50-80x reveals the cross-shaped pattern of brighter stars overlaid on a field of fainter members. Look for the small, compact companion cluster NGC 1907 just to the south — the two make an attractive pair. Best observed from November through March.
History
Discovered by Giovanni Battista Hodierna before 1654. Charles Messier cataloged it on September 25, 1764. Messier described it as 'a cluster of small stars in Auriga, near the star Sigma.'
Fun Facts
The three Auriga Messier clusters (M36, M37, M38) lie at similar distances (4,100-4,500 light-years) but have very different ages: M36 is 25 million years, M38 is 220 million years, and M37 is about 350-550 million years old. Comparing them shows how clusters evolve — from hot blue stars (M36) to a mix with red giants (M37).
Community Photos (1)
Credit: gjdonatiello. License: CC0. (Wikimedia Commons)
Skybred Feb 28, 2026