Arp 33

  10-inch Newtonian, StarlightXpress MX716, 61 minutes, 11.5' x 11'

   This is one of the "double Arps".  The two galaxies in the southeast (lower-left) corner of the image make up Arp 33 field.  The chain of seven galaxies, including Arp 33, running almost the entire length of the field is Arp 326. The Atlas note says "position of larger spiral.  See 326 for smaller scale picture.  Part of galaxy chain".  The image was acquired on two nights about three months apart and the orientation of the camera was changed 90 degrees between the images.  The overlapping part was only about 11.5' x 11'.  The rest was cropped away.

Arp 33 is in the Integral Sign class, entirely because of the primary galaxy UGC 8613.  I suspect that the other galaxy in the Arp 33 field just happened to be on the plate Arp used.  It is definitely a part of Arp 326, however.  This is certainly a faint and distant group.  Whenever I look at this image, my reaction is that it is a wide-field shot of a bright galaxy group.  Then I remember that it is actually a smaller than normal field, not a large one.

When I took my first look at the calibrated and stacked raw image, I was sure I had made an error in the stacking.  I've never seen a field with so many nearly equal pairs of stars.  With my intuitive definition of "nearly equal", I count at least 15 pairs.

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