M16, the Eagle Nebula, in Ha only

M16 - The Eagle Nebula - July 25 & 27, 2019
WO-GT102 APO (4" f/5.6) refractor and ASI1600mm Pro Camera
42x300 sec Ha subs

Summer offers some of the most interesting and colorful deep space objects in the night sky. This is because the arm of the Milky Way stretches up from the southern horizon revealing a bunch of bright nebulae. Unfortunately, my telescopes are set up in my backyard and the property is sort of "in a bowl" so to speak - trees line the horizon all the way around blocking any object lower than about 20-25 degrees in altitude. So whenever the skies are clear enough to capture some of these objects I have a limited window in which to get them.

Over the last month or two I've been attempting to capture M16, the Eagle Nebula, in SHO narrowband. As I mentioned in my last post, I ran into all kinds of problems - equipment failures, cloudy or poor sky conditions, etc. Bottom line is that never got good data in Oiii or Sii (the O and S in the SHO Hubble pallette). Not to let that bug me I decided to take the good Ha data and process a monochrome, Ha-only image of M16.

So here it is in all its B&W glory. In turns out that monochrome Ha data can be extremely interesting as it tends to show more of the finer, more tenuous detail in the outer edges of the nebula. Once I get the remaining Oiii and Sii data I can reprocess the image in color - that is, if I can get the data within the next week or so as M16 is setting earlier and earlier each night and soon will be out of my view. Forecast is for clear nights this week, so who knows - maybe I can get the remaining subs.

The Eagle Nebula is part of a diffuse emission nebula, or H II region (Ha). This region is known to contain active star formation and is about 7000 light-years distant. The cluster associated with the nebula has approximately 8100 stars and it is this group of stars that are the source of the energy that makes the nebula glow. Because this was taken with my short focal length, wide field refractor, the famous "Pillars of Creation" are a bit difficult to see. The Pillars were made famous in a 1995 Hubble telescope photo and has become the most recognizable Hubble image. Maybe next year, when I replace my defective large scope mount, I'll capture this again with much higher magnification and resolution.