Instrument

12.5" RCOS @  ~f/9 (2880 mm fl) 0.64 arcsec / pixel.  The Zoomify image scale is 0.85 to 2.65 arcsec / pixel.

Mount

Paramount ME

Camera

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

Acquisition Data

10/26/2010 to 11/25/2010 Chino Valley, AZ... with CCDAutoPilot3 & CCDSoft.  AOL guided

Exposure

Lum (no filter)  435 min (27 x 15 min, bin 1x1)

Ha                  300 min (10 x 30 min, bin 1x1)

RGB                225 min (  5 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 3.0 beta (g-r) color balancing, using 125 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 RGB combine

• PhotoShop for non-linear stretching, LRGB 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 right.

Discovered by William Herschel in 1784. NGC 7331 is often touted as a twin to our own Milky Way. About 50 million light-years distant in the northern constellation Pegasus, NGC 7331 was recognized early on as a spiral nebula and is actually one of the brighter galaxies not included in Charles Messier's famous 18th century catalog..