Focal Pointe Observatory
Astrophotography by Bob Franke

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NGC 3239 (ARP 263)

       Click the full screen zoom button           ^
Click the image to Zoom and Pan              

Click here to view the image without Zoomify (3600 x 2400 - 724 KB)




12.5" RCOS @  ~f/9 (2897 mm fl) 0.641 arcsec / pixel.  The Zoomify image scale is 0.64 to 3.08 arcsec / pixel.


Paramount ME


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

Acquisition Data

1/11/2010 to 3/5/2011 Chino Valley, AZ... with CCDAutoPilot3 & CCDSoft.  AOL guided


Lum 360 min (24 x 15 min, bin 1x1)

Ha   570 min (19 x 30 min, bin 1x1)

RGB  675 min (15 x 15 min each, bin 2x2)


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 4 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 top.

NGC 3239, ARP 263, is a highly disturbed and irregular galaxy. It is located in the constellation Leo, at a distance of about 49 million light-years. In 1999, J. R. Hargis and Caroline Simpson stated that the galaxy shows signs of both early and late effects of interaction with another galaxy. Unfortunately, the other galaxy has not been identified.

The NED database identifies 91 HII regions in NGC 3239. However, these regions are difficult to show... even with added Ha filtered data.

This area of the sky is rich in background galaxies. A negative color view, of this image, reveals over 2800 galaxies... down to magnitude 23.