There are two "open" star clusters in this image. In the lower left is a portion of M35, and in the upper right corner is the far more distant cluster NGC2158. The stars in NGC2158 are yellow and red because they are much older than the younger stars in M35. NGC 2158 is ten times more distant than M35.
Open Star Clusters M35 and NGC2158
Date Taken:December 29, 2008
Location Taken: Conditions of Location:FWHM 2.0
Equipment Used:14.5" Ritchey-Chretien telescope, SBIG STL11000 CCD camera, Astrodon RGB filters, TCC, PIR, remote guide head used with Takahashi Sky90 for autoguiding, T-Point used for polar alignment (required for each imaging session due to my portable setup) with 0.7' polar alignment accuracy after two 12-star mapping runs.
Processing Used:12x90 seconds RGB, guided, processed in Maxim DL and Photoshop (total exposure 54 minutes)
Distance from Location:2,800 light years (M35)
Constellation:Gemini (the "twins")
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