NGC 609, Open Star Cluster
NGC 609 is a star cluster in the constellation Cassiopeia, which is quite far away from us - namely 13,000 light years. This results in its low
total visual brightness of only 11mag, which makes it difficult to see with small telescopes. With an angular extent of only 3' it also seems
rather small to us, but nevertheless its true diameter calculates to 11 lightyears. On deep exposed images you can see the great stellar richness
of NGC 609.
In the near vicinity are three brighter 9...10mag stars, one of them is a beautiful double star with the designation "MLB 187". The two 9.0mag
and 9.5mag bright components are 5.3" (arcseconds) apart.
----------------------------------------------------------------------------------------------------------------------------------------------
With an aperture of 20 inches, NGC 609 shows up at a magnification of 120x as a fairly bright, slightly grainy spot of light that is easy to
hold with indirect vision.
If you increase the magnification to 270x, the cluster appears as glittering star dust in front of a grainy background, from which many very
faint stars flash out, only to disappear in the next second. Altogether 15-20 single stars are visible, all fainter than 14...15mag. The center
appears slightly dimmer. A nice small asterism of 12...13mag stars is at the southwestern edge.
