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Deepsky Top-100 (14): NGC 457

When you scan Cassiopeia and its neighbouring constellations with binoculars, the star fields in Cassiopeia seem to be much richer than in Perseus and Cepheus. The reason for this is that in the Perseus and Cepheus Milky Way, large nearby dust clouds of our own spiral arm (the Orion arm) block the view, while in the Cassiopeia Milky Way there are no dust clouds to block the view. You actually look through a "window", across an inter-arm gap towards the Perseus arm, the next spiral arm toward the exterior of our galaxy.

In Cassiopeia you can find a large variety of open clusters. Because you can look over great distances through the Cassiopeia window, you see clusters lying at very different distances from us. Some clusters are "foreground" clusters that lie relatively nearby (Stock 2, NGC 225), some lie scattered across the inter-arm gap between our own Orion arm and the Perseus arm (M52, NGC 7789), while others actually lie in the Perseus arm. NGC 457 is on of them. This open cluster lies in the Perseus arm at a distance of 9,900 light-years away from us.

Locating this fine open cluster that was discovered by William Herschel in 1787, is very easy. From delta Cassiopeia go 2 degrees south-southwest. There you will find NGC 457. On the finder chart below the circle represents the 4 degree field of a standard finder telescope.


Finder chart for NGC 457. Limiting magnitude 6.5
Credit and copyright SkyTools 2 by Capellasoft

Click here to download a printable finder chart (PDF)

With a magnitude of 6.4, NGC 457 is one of the brightest open clusters in Cassiopeia. It contains about 80 to 100 stars, spread over an area of 16'. When you first look at the cluster through big binoculars or a telescope, you might think you see a little man, a bird (owl), or even ET waving at you. To me NGC 457 looks like a man with two bright sparkling eyes, his arms widely spread to welcome me. The two eyes are two bright stars, that will draw your attention immediately. They stand out well from the rest of the cluster. The brighter of the two stars is Phi Cassiopeia, a yellow star of magnitude 5.0. The other is HD 7902, a blue star of magnitude 7.

In my 15x80 binoculars I see about 20 to 30 stars up to magnitude 10, when observing from my backyard. The "body" of the man is made up of a 13' long northwest-southeast bar of stars. The arms are clearly visible. The feet are hard to see but sometimes pop in to view as 4 or 5 stars in an arc at the end of the long bar. In the 8-inch telescope NGC 457 is just lovely. It is by far superior to the Messier clusters of Cassiopeia, M 52 and M 103. Together with Stock 2 and NGC 7789, NGC 457 makes up my top three list of open clusters in Cassiopeia!

Go and check out NGC 457, a friendly man (owl or ET) with two bright eyes, his arms spread out to greet you. A great sight.



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