NGC 1220, Open Star Cluster
The star cluster NGC 1220 is a rather inconspicuous object in the northern part of the constellation Perseus. It lies only about 1° east
of the 2.9mag bright star "gamma Per" and is therefore quite easy to find. With an apparent diameter of only 1.5' to 2' and a brightness
of 11.8mag it is rather an object for telescopes with 10" aperture and larger.
The distance to NGC 1220 is given as 5.900 light years. Therefore the true size can be determined to about 3 light years. A recent
study has identified 26 members belonging to NGC 1220. The brightest star has an apparent magnitude of 13.1mag, from which its
luminosity can be calculated to 16 suns. The Cluster also appears to be a fairly young object, with an age of 60 million years. It lies
in the Perseus arm of our Milky Way, but is located about 400 light years above the galactic plane. It is not yet clear whether it
formed there or migrated there over millions of years.
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In my 20" telescope, NGC 1220 appears inconspicuous, small, compact and roundish at a magnification of V=270x. A total of 10 to 15
faint individual stars are visible. The brightest stars with a brightness of 13...14mag are located at the western edge. A very faint background
glow can be perceived, from which very faint stars flash out now and then. Another noticeable feature is the lack of stars in the surrounding
area. Bright stars are completely missing.
