| Description | As expected for a large Messier object, this is an extremely bright target. The toughest aspect was to set the black level appropriately to show the diffuse outer ring of this nebulous, elliptical galaxy... It's so large, I thought for a while my dark-subtraction in SharpCap was failing, and I was seeing amp glow! However, I was able to identify that the diffusion wasn't quite round, and not "quite" as large as uncontrolled amp-glow with my 294 sensor. This became obvious after about 15m of integration. The S/N ratio was so high, and since there is no structure to speak of in the outer disc, there seemed no advantage to continuing integration longer than the 25m once the two tiny galaxies, LEDA 139919 and UGC 7652, were clear. At first, I thought the dust lane connecting these small galaxies to the galactic center were the "jets" referenced in the Arp Category text. Then a friend pointed out that it's actually a tiny bump on the edge of the galactic core. You can see it if you enlarge the featured image, and an enlarged closeup is in the gallery. It is barely visible in the Arp photograph; note the Arp comparison is rotated 180° relative to the original capture, featured image, and jet enlargement. |
