Object Information:

 

The Double Cluster in Perseus, NGC 869 and NGC 884
Distance -  7,000 light years

The dense grouping of stars in the image above is known as an open cluster [sometimes also known as a "galactic cluster"].   Open clusters are believed to originate in the same general area of space from the same local gas clouds. 

The famous double cluster in Perseus was known in historic times (probably even pre-historically), and first cataloged by the Greek astronomer Hipparcos.

Both clusters are situated in the Perseus OB 1 association, and also only a few hundred light-years apart, at a distance of over 7000 light years. They are both quite young: NGC 869 is listed at 5.6, NGC 884 at 3.2 million years (Sky Catalog 2000); their hottest main sequence stars are of spectral type B0. They are approaching us at 22 (NGC 869) and 21 (NGC 884) km/sec, respectively.

For more information on open star clusters see:

http://www.seds.org/messier/open.html

http://www.seds.org/messier/xtra/ngc/n0869.html

  Imaged at: 

 

Grandview Campground, Inyo National Forest, CA

  Equipment:  

 

Optics - Takahashi Epsilon 160
Mount - Astro-Physics 900 GTO,
Camera - Santa Barbara Instrument Group (SBIG) ST-2000XM CCD,

Filters - RGB

  Exposure Information:

 

September 17, 2004

 

RGB Image - 120 sec. each;  Each color component is a median combination of 5 sub-exposures. 

  Camera Control Software:

 

MaxIm DL 4

  Image Processing Software:

 

Image calibration and registration with Mira 6; RGB combination in MaxIm DL; final processing in Photoshop 8