Instrument

12.5" RCOS @  ~f/9 (2880 mm fl). Imaged at 0.64 arcsec/pixel,  shown at  0.85 and 2.69.

Mount

Paramount ME

Camera

SBIG STL-11000 w/ FW8 filter wheel, AstroDon Filters

Acquisition Data

11/13/2012 to 1/8/2013  Chino Valley, AZ. with CCDSoft and CCDAutoPilot

Exposure

Lum    660 min. (22 x 30 min. bin 1x1)

RGB    450 min. (10 x 15 min. bin 2x2) each

Software

• CCDSoft, CCDStack, PixInsight and Photoshop CS6.

• eXcalibrator v4.25 for (g:r) color balancing, using 37 stars from the SDSS-DR9 database.

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

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

• PixInsight for gradient removal, initial non-linear stretching, noise reduction and selective HDRMultiscaleTransform.

• PhotoShop to create the LRGB final touch-up.

• Noiseware 5 for background touch-up.

Comment

North is to the top.

This colorful cosmic skyscape features a peculiar system of galaxies cataloged as Arp 227 some 100 million light-years distant. Swimming within the boundaries of the constellation Pisces, Arp 227 consists of the two galaxies prominent on the left; the curious shell galaxy NGC 474 and its blue, spiral-armed neighbor NGC 470. The faint, wide arcs or shells of NGC 474 could have been formed by a gravitational encounter with neighbor NGC 470. Alternately the shells could be caused by a merger with a smaller galaxy producing an effect analogous to ripples across the surface of a pond. Remarkably, the large galaxy on the right hand side of the image, NGC 467, appears to be surrounded by faint shells too, evidence of another interacting galaxy system. Background galaxies are scattered around the field that also includes spiky foreground stars. Of course, those stars lie well within our own Milky Way Galaxy. 

Source: NASA APOD