Instrument

12.5" RCOS @  ~f/9 (2880 mm fl) 0.64 arcsec / pixel.  The Zoomify image scale is 0.85 to 2.56 arcsec / pixel.

Mount

Paramount ME

Camera

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

Acquisition Data

10/27/2010 to 1/28/2011 Chino Valley, AZ... with CCDAutoPilot3 & CCDSoft.  AOL guided

Exposure

Lum (no filter)  435 min (29 x 15 min, bin 1x1)

Ha                  900 min (30 x 30 min, bin 1x1)

RGB                630 min (14 x 15 min each, bin 2x2)

Software

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

eXcalibrator for (u-g), (g-r) color calibration, using 15 stars from the SDSS-DR7 database.

PixFix32 (pre-beta) to repair column defects.

CCDStack to calibrate, register, normalize, data reject,  combining the sub exposures and LRGB combine

PhotoShop for non-linear stretching, LLRGB combine and adding the Ha data to the red channel, with the lighten setting for opacity.

Noiseware Pro, a PhotoShop plug-in.

North is to the bottom.

NGC 2403, discovered by William Herschel in 1788, is an intermediate spiral galaxy in the constellation Camelopardalis. At a distance of eight to ten million light-years, the galaxy is an outlying member of the M81 group. Scattered thought the galaxy are many HII regions. Nearly 1000 are identified in the NED database. At least six of these hydrogen clouds are considered giant HII regions, possibly fifty times larger than the Orion cloud in our galaxy.