M31 – Spiral Galaxy in Andromeda

Telescope: Meade N6 at f/5, Orion Atlas EQ-G
Camera: Full-spectrum Modified Canon 600D, Orion Imaging Skyglow Filter
Guide scope: Williams Optics 50mm, Meade DSI Pro III, PHD
Exposure: 44x60sec ISO 800 saved as RAW
Darks: Internal (Long Exposure Noise Reduction On)
Flat: 32x3sec, ISO 800, LED tracing tablet covered with 3 layers of muslin
Average Light Pollution: Red zone, fair transparency
Lensed Sky Quality Meter: 18.6 mag/arc-sec^2
Stacking: Mean with a 2-sigma clip.
White Balance: Nebulosity Automatic
Software: Backyard EOS, Nebulosity, Deep Sky Stacker, Photoshop

M31 is definitely one of my major challenge objects and I usually avoid it unless the conditions are perfect. It is so large and spans such a huge dynamic range it requires absolutely perfect transparency to have any hope of capturing the outer arms. This particular evening wasn’t the best, but I was testing a new guidescope installation and since I have never imaged M31 with my N6 I was curious to see how it would be framed.

M31 is an iconic spiral in the constellation of Andromeda (The Princess). It is very well placed in the northeast throughout the fall. Under dark skies it is easily visible to the naked eye and from urban skies it is an easy object for binoculars and small telescopes. At a distance of some 2 million light years, it is the farthest objects easily visible to the naked eye. M31 also has several satellite galaxies, two of which are visible here. M32 is about as bright as the core of M31 and is located at the bottom of this field. To the upper right is the much fainter M110. It is easy to be disappointed with the visual appearance of M31 since it is often shown in highly processed images. However, the true appearance is quite beautiful in its own way. The core is relatively bright and almost stellar, surrounded by a soft luminous glow that gradually fades into the background sky.

-John

M31 (11-23-2017)-1j.jpg