NGC 457: The Owl Cluster
Sketch and Details by Frank McCabe
At a distance of 9,300 light years (2850 parsecs) this youthful open cluster is about the same age as the Perseus Double Cluster – eight million years old. NGC 457 in Cassiopeiae is composed of nearly 100 stars brighter than magnitude 13 and many fainter members. The cluster has several names including the Owl cluster, the E.T. cluster, the Phi Cas. cluster and others. The two brightest stars here, Phi Cas. and HD7902 may not actually be members of this open cluster but rather foreground stars. These two stars form the bright eyes of the owl. Phi Cas. is a magnitude 5 yellow star and HD 7902 is a magnitude 7 bluish star. If the brighter member is a cluster star at 9,000 light years it would have a luminosity of 275,000 suns. The integrated visual magnitude of this cluster is about 6.4 and it is 16’ across. This object was discovered by William Herschel in 1787. It can easily be found 2° south-southwest of delta Cas. (R. A. 1h. 22’, Dec. +58° 2’).
Sketching
Date and Time: 8-11-2008, 5:20-6:40 UT
Scope: 10” f/5.7 Dobsonian. 13mm eyepiece 111x
8”x11” white recycled sketching paper, 4B soft charcoal pencil, HB hard charcoal pencil, blending stump, scanned and inverted, some star magnitude adjustment made at the time of scanning.
Seeing: Pickering 5/10
Transparency: Average 3/5
Nelm: 4.2
Frank McCabe
Frank,
I’m happy for you that you got some quality time in deep-sky. And you choose an excellent target.
Wonderful sketch of one of my favorite clusters!
Rony
Rony,
Thank you. I don’t have good dark sky at home so I make the best of it or try driving to darker sites.
Frank