M35 and NGC 2158 - Open Star Cluster in Gemini


Copyright 2007 Hap Griffin

This photograph shows two distinctly different types of open clusters...collections of stars of similar origin and loosely bound by gravity.  The two clusters, while appearing together in the sky visually, are actually very far apart.  M35 in the center lies at a distance of 2700 light years while the dimmer NGC 2158 lies 15,000 light years away.  M35 is a relatively young cluster at around 956 million years of age and still possesses mostly hot blue and white stars.  On the other hand, NGC 2158 is much older...over one billion years.  Over the eons, the hotter stars have lived out their lives and vanished as novae or supernovae leaving only the cooler orange and yellow stars behind.   

M35 can be seen by the unaided eye from dark locations as a fuzzy patch near the three "foot" stars of the constellation Gemini.  


Date/Location:    December 17, 2007     Griffin/Hunter II Observatory    Bethune, SC
Instrument:    Canon 40D (modified IR filtering) Digital SLR through 10" Newtonian w/MPCC 
Focal Ratio:   f/ 4.7
Guiding:    SBIG ST-237 through Orion ED80
Conditions:    Cold and clear
Weather:    30 F
Exposure: 41 minutes total (41 x 1 minute @ ISO 800)
Filters:    Baader UV/IR block internal to camera
Processing:    Focused and captured,  RAW to TIFF conversion, flat frame calibration, Digital Development, resizing and JPEG conversion in ImagesPlus.  Final tweaking in Photoshop CS2.