Instrument

12.5" RCOS @  ~f/9 (2880 mm fl) at 1.28 arcsec / pixel.  Zoomify image scale is 1.65 to 2.203 arcsec / pixel.

Mount

Paramount ME

Camera

SBIG STL-11000 w/ internal filter wheel, AstroDon Gen-1 Filters

Acquisition Data

2/14/2009 to 3/4/2009 Chino Valley, AZ... with CCDAutoPilot3 & CCDSoft.

Exposure

Lum  150 min. ( 10 x 15 min. bin 2x2)

RGB  180 min. ( 4 x 15 min. bin 2x2, each)

Software & Processing Notes

CCDSoft, CCDStack, Photoshop CS w/ the Fits Liberator plugin, Noel Carboni's actions and Russell Croman's GradientXTerminator.

PixFix32 (pre-beta) to repair hot/cold pixels and column defects.

CCDStack to calibrate, register, normalize, data reject, combine sub exposures & color combine for the LRGB.

PhotoShop CS3 for non-linear stretching and LLRGB combine

Comment

North is to the top

M38 was discovered by Giovanni Batista Hodierna before 1654 and independently found by Le Gentil in 1749.

The cluster spans roughly 25 light-years and lies about 4000 light-years away toward the constellation of Auriga. M38 is about 220 million years old, still young enough to have many young bright blue stars. Clusters, like this, are loosely bound by gravity. As they age, the clusters spread out and the member stars slowly escape.