NGC 869, and NGC 884 in Perseus are two open clusters of stars meaning they are relatively young stars estimated at 12.8 million years old. Both clusters lie at a distance of 7500 light years from Earth. NGC 869 has a higher mass than NGC 884 with 869 being around 3700 solar masses and 884 being 2800 solar masses. Recent research has found that both clusters are surrounded with a halo of stars making the total mass for the complex at lease 20000 solar masses. This object was noted as early as 130 B.C by the Greek astronomer Hipparchus who claims it to be a patch of light in Perseus. In the early 19th century, William Herschel was the first to recognize it as two separate open clusters. Although the pair are bright, and can be seen with the unaided eye, it was not included in Messier’s catalog (most likely because it didn’t look “comet like” to Charles Messier), but it is included in the Caldwell catalog.
Through the eyepiece this double cluster is visually stunning, with the orange bright stars shining bright with dimmer white/blue stars gathered together in two separate formations. One of my favorite fall/winter clusters which never disappoint to an astronomy pro or newcomer.
This image is 45 light frames at 2 minutes and ISO 800, 48 dark frames, 35 flat frames, and 52 bias frames. Images stacked in Deep Sky Stacker, and post processing done in Photoshop.
Omni XLT 150 with CG-4 mount
Modded Canon 350D
T-ring and adapter
Polar Scope for alignment