Messier 20 The Trifid Nebula


Messier 20, also known as the Trifid Nebula, is one of Sagittarius’s most imaged and beautiful deep sky objects. The object has red emission, blue reflection, and dark nebula in this one object.

The nebula has an open cluster in the middle. This is also an active star-forming region. The Trifid is about 300,000 years old and about 9000 light-years away.

Charles Messier discovered M20 on June 5, 1764.

I took this image at Cherry Springs State Park in Pennsylvania. This is an IDA dark site with minimal light pollution.

Processing Info

I stacked the 28 light frames along with 40 dark and 40 flat frames in PixInsight.

The following processes were performed in PixInsight:

  • Dynamic Crop
  • Automatic Background Extraction
  • Photometric Color Calibration
  • MultiScale Linear Transform
  • Histogram Transformation
  • LRGB Combination
  • Curves Transformation (X2 with a range mask. Inverted mask for the background and then non inverted for the target)
  • Morphological Transformation (Generated StarMask using default settings)
  • Local Histogram Equalization (Performed with a range mask)

Once I found what I liked, I saved the files, went to Photoshop, and ran Topaz AI DeNoise. This is an amazing plugin that works like magic.

The area of the sky in SagittariusHere you can see the area of the sky in Sagittarius imaged.

Acquisition Data

  • Telescope: Explore Scientific ED127 Air-Spaced Triplet Apochromatic Refractor
  • Camera: ASI2600MC Pro
  • Guide Scope: Orion ST80
  • Guide Camera: ASI290MM Mini. Dithering every image at 1 pixel each time
  • Mount: iOptron CEM60
  • Software: NINA for image acquisition. PixInsight is used for tacking and editing. Imported to Photoshop for final touchup and watermarking
  • Other Accessories: AstroZap Dew Heater, Explore Scientific 2″ Field Flattener, MoonLite CFL 2.5″ Focuser, High Res Stepper Motor, V3 Controller, Pegasus Astro Power Box Advance
  • Filters: Optolong L-Pro 2″
  • Exposure Time: 1 hours 52 minutes (28 x 240 seconds) -10°C, 100gain, bin 1×1
  • Exposure Start: 22:24
  • Date: August 14, 2020
  • Location: Cherry Springs State Park, Pennsylvania, USA
  • GPS Coordinates: Lat. 41.6628445, Long. -77.8230494
  • Temperature: 64°F/17.7°C
  • Bortle Dark-Sky Scale: 2
  • job: 3918452
  • Avg. Moon age: 25.72 Days
  • Avg. Moon phase: 15.54%
  • RA center: 18h 2′ 35″
  • DEC center: -22° 56′ 24″
  • Orientation: 303.142 degrees
  • Field radius: 0.698 degrees
  • Magnitude: 7.6
  • Resolution: 3720 x 2330