Instrument

12.5" RCOS @  ~f/9 (2880 mm fl) 0.64 arcsec / pixel.  The Zoomify image scale is 1.28 to 3.33 arcsec / pixel.

Mount

Paramount ME

Camera

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

Acquisition Data

10/30/2011 to 12/25/2011 Chino Valley, AZ... with CCDAutoPilot3 & CCDSoft.  AOL guided

Exposure

Lum  465 min. (31 x 15 min. bin 1x1)

RGB  540 min. (12 x 15 min. each, bin 2x2)

Software

• CCDSoft, CCDStack, Photoshop CS and Noel Carboni's actions.

• For color balancing, a few NOMAD1 stars were selected by hand to determine the white reference with eXcalibrator's manual calibration method.

• PixFix32 (pre-beta) to repair column defects.

• CCDStack to calibrate, register, normalize, data reject, combine the sub exposures and create the RGB color image.

• PixInsight for on-linear stretching.

• PhotoShop for the LRGB combine and final tweaks.

• Noiseware Pro, a PhotoShop plug-in.

North is ~ to the top.  The image is rotated 35° clockwise.

This group of nebulae is located in the constellation Auriga. The bright blue reflection nebula is vdB31. In 1966 Sidney van den Bergh published a catalog of 158 reflection nebulae.

As the name implies, reflection nebulae are clouds of dust that reflect the light of a nearby star or stars. They appear blue because the nebula more efficiently scatters blue light. This is the same reason why our sky appears blue.

The other objects of interest are three dark nebulae, cataloged by Edward Barnard as B26, B27 and B28. Starting in about 1919 Barnard photographed and cataloged 370 dark nebulae.

A dark nebula is a dense interstellar cloud that obscures the light of objects behind it. The clouds are composed of very small dust particles, coated with frozen carbon monoxide and nitrogen. These dark clouds are spawning regions for stars and planets.