Double double in NGC1502

NGC1502 open cluster in Camelopardalis

There is not much to see in Camelopardalis (The Giraffe) for casual observer. Even to see a few of its brightest stars you need dark skies. With binoculars though you can pick some pretty sights, and one example is Kemble’s Cascade. The stars in this asterism are not related to each other – they just happen to line up in the sky.

At the one end of Kemble’s Cascade there is group of 45 stars that are related: it is NGC1502 open cluster. This cluster is placed about 3300 light years away, and its age is uncertain. One clue to cluster’s age is the types of stars the cluster contains. Many of then are hotter and bigger than Sun, and such stars cannot live very long. That can mean that cluster cannot be very old – it is estimated at 5 million years. Inside the cluster there is pretty double star Struve 485 with two bright members (7.1 + 7.0 mag) separated by 18 arc seconds, and next to it there is Struve 484 double star – closer and fainter. The cluster itself is pretty compact – its apparent diameter is only about 8 arc minutes. It was discovered by William Herschel on November 3, 1787.

Image below was made with Meade ACF 10″ f/10 telescope with CCDT67 compressor, QHY163M camera and EQ6 mount. It is 48 minutes of exposures with RGB filters under suburban sky. Both transparency and seeing were poor.

Struve 485 and 484 double stars in NGC1502 center

At this sketch description by Eric Graff you can read that in The Catalogue of Components of Double and Multiple Stars lists 16 members of STF485. 

Clear skies!

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