The Trifid Nebula - Messier 20
The Trifid Nebula, also called M20 or NGC 6514, is located in the direction of the constellation Sagittarius, Latin for "archer", depicted as a Centaur, a half human and half horse mythical creature. It is an HII region, meaning it is interstellar atomic hydrogen that has been ionized. Like many HII regions, M20 is a star-forming region, but it is also an open star cluster, an emission nebula, a reflection nebula, and a dark nebula all rolled into one area of the sky. M20 is literally forming stars today and is located in our own Milky Way galaxy. M20 has already birthed a massive star that is about 20 times the mass of our sun and surrounded by 3100 other young stars. The region on the right of this image glows red since Ultraviolet (UV) light of surrounding stars ionizes (removes electrons from) the interstellar hydrogen gas. This gas, now positively charged, then easily recaptures negatively charged electrons resulting in an emission of a photon of light called hydrogen-alpha light seen as red on film and in CCD cameras! However, the region on the left of this image that glows blue is merely reflecting this same UV light which naturally appears blue on film and in CCD cameras. The dark lanes of material are called dark nebula that blocks light from penetrating its material. These dark areas have another name, Barnard 85 as cataloged by E.E. Barnard in the late 19th and early 20th century. In January of 2005, NASA's Spitzer Space Telescope discovered 30 embryonic stars and 120 newborn stars not yet seen in visible light. The Trifid Nebula is about 5000 light years away from Earth, and so it is very possible that other infant stars have turned on their nuclear fusion, but whose light has not yet reached us. Below is the same image as above but with older processing techniques which I have now improved upon. Note the more balanced colors, tighter star images, sharper dust and gas lanes, and better star spokes caused by the 20-inch mirrored telescope "vanes" that hold the secondary 7-inch mirror. The stats for M20 are as follows: Bright Emission/Reflection and Dark Nebula, RA 18h 02m 25s, Dec -22° 59' 00" Mag: 9.0, Size: 17.0'x12.0', Class: E+R.
Optics: RC Optical System 20" F/8.2 (4165.6 mm Focal Length) Date: July - Oct 2015
Camera: SBIG STXL-11000 with Adaptive Optics Location: Columbus, Texas
Exposure: LRGB = 270:100:60:100 minutes Imager: Kent E. Biggs