I recently posted that Messier 8 with the Lagoon Nebula was my favorite summertime sight. Well, I have another to add to the list. Messier 20, otherwise known as the Trifid Nebula, is another stunning sight. It's hard to tell exactly how "Trifid" was decided upon. You can clearly see the two distinctly colored regions. The reddish colored portion is an H-II region glowing in red hydrogen-alpha light while the bluish area is a reflection nebula. As the name implies, it is literally clouds of interstellar dust that are reflecting the light. So, if you count these two regions, perhaps it should be called the Bifid nebula? Another approach is to look closely at the reddish portion as it appears to be divided into parts by dark, dusky lanes. However, it appears to be divided into four. So, should it be then called the Quadfid nebula? Perhaps "Trifid" just had a nice ring to it and the name stuck. This nebula, by galactic standards, is fairly young at under 400,000 years and, like many other nebulae, is an active star forming region.
The other main object in the photo, aside from the 5000+ stars, is Messier 21. This one also suffers from its location relative to the much more spectacular M20. It's in the upper left quadrant of the photo and resembles a diamond ring. Can you spot it?
Messier 20 (Trifid Nebula) & Messier 21
August 14-15, 2014
Orion 8" Astrograph on VX Mount
Nikon D3100 Camera - ISO 1600
Baader MPC Mark III Multi-Purpose Coma Corrector
Skyglow filter
Autoguider
35 sub-frames at 3.0 minutes/frame
Total Exposure Time = 1 hour 45 minutes
Image Stacking in Deep Sky Tracker
Image Processing in PhotoShop
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