TRIFID NEBULA, MESSIER 20 (M20)
September 6 and 7, 2023The Trifid Nebula is a relatively young (300,000 years old) star-forming Hii region in the Milky Way’s Saggitarius arm. Its name, Trifid, means “three-lobed," referring to the way it looks, and fact that it is an unusual combination of a star cluster, an emission nebula (the dense reddish-pink portion), a reflection nebula (the blue-colored portion), and a dark nebula, which creates the dark gaps and its trifurcated appearance. It is popular among amateur astronomers because it is relatively bright (Magnitude 6.3) and can be easily observed with a small telescope. Lying 5200 light-years distant, the Trifid Nebula subtends an angle of 28 arc-mins, just shy of the diameter of a full Moon.

 A bright, open cluster of young, hot O-type stars lie at the core of the emission nebula, partially obscured by thick dust lanes that block visible light. The intense radiation of the stars has blown away the dust and gas in the region surrounding the cluster. As a result, there is no longer any star-forming activity in the vicinity of the Trifid Nebula. Interestingly, the blue reflection nebula observed in images is not physically associated with the Trifid Nebula, but just happens to appear along the same line of sight.

Focus: Vega was 4.9-5.0 FWHM, with smaller stars around M8 having 2.3-2.5 FWHM

Exposure Information:·        Lights: 84x frames, 46x 60 seconds, 38x 90 seconds·        Darks: 50x 60sec, 50x 90sec·        4x Master Darks (2x 60sec, 2x 90sec)·        1x Master Bias·        2x Bad Pixel Maps (1 created this session)

Equipment and Software·       
AstroTech AT70ED with ATR8 0.8x FF/Reducer and IDAS LPS-D3 filter imaged by an Ha-modified Canon T3i·       
Mount: EQM-35Pro with ASI 120-MM-mini with ZWO 30mm f/4 guide scope and camera controlled by PHD2·       
Session Control via BeeLink mini-PC running EQASCOM, Carte du Ciel, ASTAP, BYEOS, Polemaster with remote control via Windows Remote Desktop from a laptop. 

The images were stacked and processed in Astro Pixel Processor, further polished in 32-bit mode using Photoshop and LightRoom, along with R-C Astro's NoiseXterminator and StarXterminator.