"The Double Open Cluster" in Perseus
NGC 869 and NGC 884

Double Open Cluster

Image Details (Click for Cropped Full Resolution Image, or for Un-Cropped Full Resolution Image):

Telescope: Astro-Physics 130 Grand Turismo @ F6.3 (819mm) w/Field Flattener
Wikipedia Notes: The Double Cluster is the common name for the naked-eye open clusters NGC 884 and NGC 869, which are close together in the constellation Perseus. NGC 884 and NGC 869 are at distances of 7600 and 6800 light-years away, respectively, so they are close to one another in space as well.

They are relatively young clusters, with NGC 869 5.6 million years and NGC 884 at 3.2 million years according to the 2000 Sky Catalogue. In comparison, the Pleiades have an estimated age ranging from 75 million years to 150 million years.

They are also blueshifted, with NGC 869 approaching Earth at a speed of 22 km/s and NGC 884 approaching at a similar speed of 21 km/s. Their hottest main sequence stars are of spectral type B0.

Mount: Astro-Physics Mach1GTO
Camera: SBIG STL11000M & Astrodon Filters
Exposure: RGB = 40:40:40 Minutes
Location: ARGO, Oregon USA
Date: October 2010