Let's start with the galaxy, which happens to be NGC4395 in the constellation of Canes Venatici. It's a very dim galaxy and in many ways the most difficult object I've had yet to process. It appears to be relatively nearby at around 14 million light years away, but has a low surface brightness. To me, that low surface brightness is interesting because is appears, by color, to be very active with blue stars. Blue stars are among the hottest stars and usually are bright. Rigel, in the constellation of Orion is a hot, blue star which is very bright. Because of the low surface brightness, and because of the blue being in the less responsive region of the camera, sort of a double whammy, even a couple of hours of light collection yielded a dim galaxy. Of course, the local light pollution works very much against acquiring dim data. Anyway, here it is.
 |
| NGC4395 |
The second issue of this post is something that I saw on the Youtube channel of Astrofarsography. He has done a few astro imaging tutorials using GIMP, which is one of the image processing programs I use. The basic idea is called Star Reduction, which in this context means reducing the brightness and (radial) size of stars with the purpose to emphasize something else, usually some nebulosity. Usually, stars are much brighter than the nebulosity and therefore more prominent. This technique lets the stars remain, but be less prominent, sort of fade into the background as it were, and allow the “something else” to “shine”. It's an artistic effect, but I think it has it's place. Used properly, I think I like it. The image is of NGC7380 in the constellation of Cepheus.
 |
| NGC7380 as initially processed. |
 |
| NGC7380, same as above, after "star reduction" |
