2015-05-14 Astrophotography: M81 and M82 Galaxies

20150514_M81_M82_ImagesPlus2-Edit (double stretch)-2-2After weeks of either clouds or bright moonlight, conditions finally came together for Astrophotography.  We had a clear night, with no moon, and I was eager to find and shoot my first Galaxy.  A common target for beginner astrophotographers is the pair of galaxies classified as Messier 81 and Messier 82.  They are located relatively close to one another and can be found by drawing a straight line from the star Phecda to Dubhe of Ursa Major and extending it again by about the same distance.

M81 and M82 are located about 12 million light years from Earth and about 150,000 light years from one another.  The two galaxies are relatively close to one another, and the gravitational pull on each other exerts forces that actually help to create the shape of one another.

Widefield view of M81 and M82 Galaxies.
Widefield view of M81 and M82 Galaxies.
A closer crop for composition to better isolate M81 and M82.
A closer cropped composition to better isolate M81 and M82.

Messier 81 (M81) is commonly known as Bode’s Galaxy.  It was discovered in 1774 by Johann Bode and has been classified as a Messier Object.  It is one of the most perfect spiral galaxies found in the night sky and it’s perfect formation is partially credited to the forces exerted on it by neighboring galaxy M82.  The active galactic nucleus of the galaxy contains a supermassive black hole with an extremely bright core surrounded by beautiful spirals.   It is a very dim object in the night sky and unobservable by the naked eye in all but the darkest sites on the planet.  Even at a dark site, conditions must be perfect for observation.

20150514_M81_M82_ImagesPlus2-Edit (double stretch)-2-2
Messier 81 (Bode’s Galaxy)

Messier 82 (M82) is affectionately known as the Cigar Galaxy.  It was also discovered by Johann Bode in 1774, and the unique shape with outflow of ionized hydrogen gas (red) is believed to be caused by a massive explosion from the galaxy core.  This explosion contained the force equivalent to that of 7,000 exploding suns.  It’s bright core and spiral (edge on to the camera) is an extremely active star creation region where stars are created at a rate of over 10 times that of our Milky Way Galaxy.

Messier 82 (The Cigar Galaxy)
Messier 82 (The Cigar Galaxy)

To image these galaxies, I used a Modified Canon Rebel T5i with a Canon 300mm f2.8 lens.  I mounted these on an Astrotrac Equatorial Tracking Mount to follow the movement of the sky as the Earth rotates allowing for long exposures without star trails.  The resulting image was created by combining 144 separate exposures of 60 seconds each, for a total exposure time of 2 hours and 24 minutes.  Dark, Flat and Bias frames were also combined and initial processing performed with ImagesPlus.  Final processing to “unlock” the data within the resulting files was performed with Adobe Photoshop and Adobe Lightroom.

Canon T5i (Modified), Canon 300mm f2.8is II, f2.8, 60 second exposures (144 for a total of 2 hours 24 minutes exposure), ISO 1600, Astrotrac, Light Pollution Filter, ImagesPlus, Photoshop, Lightroom.  144 Light Frames, 28 Dark Frames, 30 Bias Frames, 25 Flat Frames 




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This Post Has 2 Comments

  1. I’m not sure exactly why but this weblog is loading extremely slow for me.

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