Messier 33 The Triangulum Galaxy

M33Click here for an annotated version of this target.

M33, also known as the Triangulum Galaxy, is a spiral galaxy about 2.73 million light-years away in the constellation Triangulum.

M33 is part of our local group of galaxies, which includes Andromeda, the Magellanic Clouds, and our very own Milky Way.

There are multiple Hydrogen II emission nebulae and star-forming regions in the target (Above you can see the annotated image with these regions indicated). At a later date, I would like to spend an equal amount of time on HA data for this target and add to this image.

M33 is a large but faint object. One can see this target with your naked eye under pristine skies. M33 has been used as a benchmark for the Bortle Dark-Sky Scale. I could not see it without and visual aids but was able to observe this with a couple of dobs at the park.

M33 is also known as the Pinwheel Galaxy, which is also a designation for M101.

M33 was first discovered by the Italian astronomer Giovanni Battista Hodierna in 1654 and then rediscovered and cataloged by Charles Messier in August of 1754.

I took this target at Cherry Springs State Park in PA. The night was cold and got down to 29°F. I woke up to frost all around me and an icy tent. This, along with a clear sky, was a welcome treat. The earlier forecast called for smoke from the California and West Coast wildfires affecting the transparency, however, the last-minute cold front blew out the smoke, and we were welcomed with some clear skies.

Processing Info

I took 72 frames at 300 seconds each. I had to throw away about two frames. Otherwise, I could have had a full 6-hour image. I stacked the 70 light frames along with 50 dark and 50 flat frames in PixInsight.

Earlier in the night, I had issues plate-solving due to a simple error on my end, which took me two hours to resolve. I could have had a much longer image if I hadn’t run into any issues. As they say, astrophotography is a learning experience every time you set up and get started.

The following processes were performed in PixInsight:

  • Dynamic Crop
  • Dynamic Background Extraction
  • Background Neutralization
  • Color Calibration
  • Photometric Color Calibration
  • MultiScale Linear Transform
  • Histogram Transformation
  • LRGBCombination
  • Curves Transformation (X2 with a range mask. Inverted mask for the background and then non inverted for the target)
  • Color Saturation
  • Curves Transformation (X2 with a second 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 and went to Photoshop. I played around with the levels, vibrance, and saturation a bit. I then ran Topaz AI DeNoise. This is an amazing plugin that works like magic.

If anyone is curious, here are the full-res versions of the images.

The area of the sky in TriangulumHere you can see the area of the sky in Triangulum 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 stacking and editing.
    Imported to Photoshop for final touchup and watermarking.
  • Other Accessories: AstroZap Dew Heater, Starizona ApexED 0.65
    Focal Reducer/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: 5 hours 50 minutes (70 x 300 seconds) -20°C.
  • Exposure Start: 22:41
  • Date: Sept 19, 2020
  • Location: Cherry Springs State Park, PA, United States
  • GPS Coordinates: Lat. 41.6628445, Long. -77.8230494
  • Temperature: 32°F/0°C
  • Bortle Dark-Sky Scale: 2
  • job: 3869227
  • Avg. Moon age: 2.36Days
  • Avg. Moon phase: 6.19%
  • RA center: 1h 33′ 55″
  • DEC center: +30° 40′ 37″
  • Orientation: 11.358 degrees
  • Field radius: 1.145 degrees
  • Magnitude: 5.72
  • Resolution: 3720 x 2330