Canon 350D Hap Griffin Baader Mod
10x180sec at iso 1600
30 Darks/Flats/Bias
Celestron 9.25 reduced 0.63

This was originally a test image to evaluate the tracking of the Atlas mount with the C9.25 at 1480mm focal length, but turned out good enough to catalog (if you ignore the dust donut from the malapplied flats).

Also known as h (869) and Chi (884), the famous double cluster in Perseus was known in antique times (probably even pre-historically), and first cataloged by the Greek astronomer Hipparcos.
Only a few hundred light-years appart, at a distance of over 7000 light years, they are both quite young: h is listed at 5.6, chi at 3.2 million years; their hottest main sequence stars are of spectral type B0. They are approaching us at 22 (h) and 21 (chi) km/sec, respectively.

August 28, 2007