Object name: NGC7798

Designation(s): NGC7798, MRK0332,

NGC 7798 is a virtually unheard of galaxy in the eastern side of the Great Square of Pegasus. I found no images of it in Astrobin nor other forms. Why it is so ignored I don\'t know. My reason for taking it was two-fold. First, with all the dust I\'m fighting I needed something bright that could cut through the smoke but not make nasty halos around the object or bright stars. Second, it is a galaxy that could have been put in Arp\'s catalog under galaxies with one heavy arm as the southern arm is much larger than the northern arm. Still, I couldn\'t find a decent amateur image of it. After lots of struggles, I think the color is about right. At least eXcalibrator is happy with it after lots of adjustments for the smoke. As a Markarian galaxy, it also attracted my interest as these sometimes can be quite interesting. This one turned out to be one of those.

One note at NED reads: \"The UV image of this spiral galaxy (Fig. 7) presents strong emission associated with the nucleus, as well as several star-forming regions along the spiral arms. The H{alpha} emission traces what is seen in the UV, and also shows strong emission along the spiral arms, outside the region covered by the UV image. The radio shows only a strong nuclear point source, and some faint emission corresponding to the spiral arms.\" At nearly 100 million light-years it is too distant for my 6nm H alpha filter to see the H alpha light so I have to trust the pros about that. NED lists it as a SBc starburst galaxy. That could explain why it is surprisingly bright for its distance. Seligman however says it is Sc?. The bar isn\'t mentioned though I do see it in my image. I measure it at a diameter of 30,000 light-years. That isn\'t all that large for one as bright as it is.

The galaxy was discovered by William Herschel on September 18, 1784. It isn\'t in either of the H400 programs which I found surprising as it is reasonably bright. Bright enough to get through my smoke.

After this image was taken we had nothing but clouds but for one sucker hole. One night they cleared and I got two nearly smokeless objects. Then the clouds returned and I\'ve been unable to do anything. Now the nearly full moon would be a problem but with clouds and rain, it doesn\'t matter. :(

Rick


http://www.mantrapskies.com/image-archive/NGC/NGC7798-MRK0332/NGC7798L4X10RGB2X10.JPG
http://www.mantrapskies.com/image-archive/NGC/NGC7798-MRK0332/NGC7798L4X10RGB2X10CROP125.JPG
http://www.mantrapskies.com/image-archive/NGC/NGC7798-MRK0332/NGC7798L4X10RGB2X10ID.JPG