Instrument

12.5" RCOS @  ~f/9 (2880 mm fl) 1.28 arcsec / pixel.  Shown resampled to 2.81 arcsec / pixel.

Mount

Paramount ME

Camera

SBIG STL-11000 w/ internal filter wheel, AstroDon Filters

Acquisition Data

3/15/2009 to 3/24/2009  Chino Valley, AZ

Exposure

Lum    100 min (10 x 10 min, bin 2x2)

Red       70 min ( 7 x 10 min, bin 2x2)

Green    70 min ( 7 x 10 min, bin 2x2)

Blue      70 min ( 7 x 10 min, bin 2x2)

eXcalibrator RGB ratios are 1.00, 0.80 & 0.78

Software

• CCDSoft, CCDStack, PixInsight & Photoshop CS6.

• eXcalibrator v4.30 for (g:r) color balancing, using 107 stars from the SDSS-DR9 database.

• CCDBand-Aid to repair KAI-11000M vertical bars.

• CCDStack to calibrate and register the sub exposures and create the RGB image..

• PixInsight processing includes registering and stacking the luminance, gradient repair and non-linear stretching.

• PhotoShop for the LRGB combine and final touch up.

Comment

North is to the bottom.  I think it looks better upside down.

Messier 67 is one of the oldest known open star clusters. M67 contains over 500 stars and lies about 2,800 light-years away in the constellation Cancer. At that estimated distance, the cluster would be about 12 light-years across.

Source: NASA APOD