Object: NGC 1502 (Hidden Treasure 23)

Magnitude A / B / C
Separation A-BC/ AC
Position angle A-BC / AC
Spectral class A / B / C
Colour A / B / C
: Camelopardalis
: 04 07.8 / +62 20
: 20
: 6.9
: 63
: 7
: 813
Detail sketch:
Date / Time
Observing Location
Seeing / Transparency
Magnification / Field of View '
: 07/12/08 / 21.00
: Landgraaf
: 3 / 3
: Orion Optics UK 300mm
: 17mm Nagler Type 4
: 94 / 52
NGC 1502

Observing Report

NGC 1502 is easy to locate. In a small telescope you can see the cluster as a very faint and fuzzy patch of light at the end of Kemble's Cascade. The cluster is bright and well detached from the background. All stars look more or less white. I cannot detect any "coloured" stars. At the centre I see two bright white stars, from which several chains of stars run into different directions. To the West of the centre there is a trapezium of stars. To the south I detect two identical triangles of stars. Beside the two bright white lucidae, there are no other striking stars in this cluster.

I count between 20 and 25 stars, which makes it a poor cluster. I can detect no nebulosity or background glow of unresolved stars. The magnitude range is large, from very bright to very faint. All in all a lovely little cluster. The optimum magnification is 94x, which is achieved with the 17mm Nagler Type 4.


At the heart of the cluster lies the bright double star Struve 485 AE, nearly equal in brightness. In fact it is a multiple star ( 9 stars according to the WDS), but the two brightest components are the two magnitude 7(B0II) stars Struve 485 A and E. The separation between the two components is 18" and the position-angle between A and E is 305°. The E component, which is in my view the northernmost of the double, is also a variable star, SZ Camelopardalis. It is a Beta-Lyrae type eclipsing binary, which changes in brightness by only 0.3 magnitudes every 2.7 days (O'Meara, Hidden Treasures). When at its maximum brightness, it is the brightest star of the cluster.

NGC 1502 is thought to be a member of the Camelopardalis OB1 association, together with to other open clusters, NGC 957 and NGC 1444. All three clusters are small, sparsely populated groups of stars, that feature one or more luminous giants of the B0/B1 II or III giants in double or multiple systems. These three clusters are probably more like enriched multiple star systems rather than true open clusters.