Messier 81 (center), Messier 82 (right), and NGC3077 (left) are a trio of galaxies that belong to the M81 group of galaxies in Ursa Major. The two bright galaxies M81 and M82, are one of the most spectacular targets to look through on a low powered eyepiece in the spring sky,
The galaxy group, which includes M81 (Bode’s Galaxy), M82 (Cigar Galaxy), NGC 3077 (Garland Galaxy), and many other Holmberg, IC, NGC, PGC, and UGC objects, are the closet galaxy group to our very own local group of galaxies which includes the Milky Way. This group and our group are together part of the Virgo Supercluster of Galaxies.
M81 is a grand design spiral galaxy that interacts gravitationally with M82, an irregular starburst galaxy. A grand design galaxy means it has well-defined spiral arms.
M82 is going through a higher than normal rate of star formation. The high rate of star formation uses up the galaxy’s molecular gas at a rate that it itself cannot sustain for much longer. It is estimated that it’ll run of fuel supply within the next couple hundred million years at its current rate. Due to the large star formation rate, a lot of these stars are high mass stars, and they have a relatively short lifetime of 10 million years. These stars are dying and going into a supernova in the galaxy. The center of the galaxy has a few clusters of stars going off into supernovae every few decades. The supernova’s high energy puffs up the core of the galaxy, and the escaping gas causes a chimney-like effect that then expels the gas from the core.
I took 210 subs, most of them at 300 and a few others at 600 seconds each. I stacked the frames with 50 dark frames and 30 flat and dark flat frames.
The following processes were performed in PixInsight:
- Channel Extraction
- Linear Fit
- Channel Combination
- Dynamic Crop
- Dynamic Background Extraction
- Automatic Background Extraction
- Background Neutralization
- Photometric Color Calibration
- EZ Decon
- EZ Denoise
- Histogram Transformation
- LRGB Combination
- Curves Transformation (X2 with a range mask. Inverted mask for the background and then non inverted for the target)
- Color Saturation (X2 with a range mask. Inverted mask for the background and then non inverted for the target)
- Curves Transformation (x3 Using multiple masks created using the GAME script)
- SCNR (Removed Green)
- EZ Star Reduction
- Local Histogram Equalization (Performed with a range mask)
- HDR Multiscale Transform
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.
Here you can see the area of the sky in Ursa Major imaged.
- Telescope: Explore Scientific FCD100 Series 127mm f/7.5 Carbon Fiber Triplet ED APO Refractor Telescope
- Camera: ZWO ASI2600MC Pro
- Guiding: ZWO Off-Axis Guider with Helical Focuser
- Guide Camera: ZWO ASI290MM Mini. Dithering every image at 1 pixel each time.
- Mount: iOptron CEM60
- Software: NINA for image acquisition. PixInsight used for stacking and editing. Imported to Photoshop for final touchup and watermarking.
- Other Accessories: AstroZap Dew Heater, Starizona Apex ED 0.65x L
Reducer/Flattener, MoonLite CFL 2.5″ Focuser, High Res Stepper Motor, V3 Controller, Pegasus Astro Power Box Advance
- Filters: Optolong L-Pro (178 x 300s), Optolong L-eXtreme (17 x 300s, 15 x 600s)
- Exposure Time: 18 hours 50 minutes -20°C
- Date: January 21 – 22, March 8 – 9, 2021
- Location: Voorhees State Park, NJ
- GPS Coordinates: Lat. 40.68187, Long. -74.89797
- Temperature: 29°F/-2°C
- Bortle Dark-Sky Scale: 4
- Avg. Moon age: 16.78 days
- Avg. Moon phase: 40.19%
- RA center: 9h 56′ 14″
- DEC center: +69° 5′ 35″
- Orientation: 63.104 degrees
- Field radius: 1.174 degrees
- Magnitude: 6.94
- Resolution: 3720 x 2330