Arp 51

This is another of the "twofers" -- Arp 51 is the tiny galaxy just south and west of the center of the field.  The larger pair north and slightly east of the center is Arp 144.  Arp 51 is in the class Spirals with Small HSB Companions on Arms, but you really need to study the 2x detail image below to see the companion.  There appear to be two.  The largest and brightest is at the end of the short linear structure pointing east, and that was probably the basis for the classification, but the brighter object northwest of the core is also likely to be a companion.  An earlier image, which can be seen on the Extras page, showed three bright points in a line on the west side of the galaxy.  They do not show up on the Atlas image, or in this new image.  I had originally thought that they might be dusty (and therefore red) star-forming regions in the galaxy.  Their absence in this longer image indicates that they were cosmic ray hits or hot pixels that were not completely calibrated out.

Atlas Image

 

  10-inch Newtonian, StarlightXpress MX716, 65 minutes, 11.7' x 10.8'
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