M31 - Andromeda Galaxy

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Click here for the Luminance/Hydrogen Alpha image

M31 is best known as the Great Andromeda Galaxy. It is the dominant member of the Local Group in which the Milky Way resides. It is 2.5 million light years away and spans approximately 260 light years. It is the farthtest object readily visible to the naked eye, appearing as a faint patch of light. If the full expanse of the galaxy were visible from Earth, it would span about six times the diameter of the full moon. It has approximately 30 satellite galaxies, most of which are dwarf galaxies. The primary ones visible in the image are M32 (the small eliptical galaxy adjacent to one of its arms) and M110 (the larger eliptical galaxy below and right). It is believed that interaction between M31 and M32 caused disturbance in its spiral structure. In approximately four billion years, the Andromeda Galaxy and the Milky Way are predicted to collide. We are approaching each other at the rate of 70 miles per second.

M31 was once known as the Great Andromeda Nebula. The existence of other galaxies was not known until 1923, when Edwin Hubble identified Cepheid variable stars in M31 and was able to conclude that it lies far outside of the Milky Way.

Telescope: APM/LZOS 152mm refractor
Mount: iOptron CEM60
Guiding: Orion SSAG on Stellarvue 50mm scope
Cameras: Luminance (L) & Ha: SBIG ST-8300 with Baader filters
Color: Modified Canon 650D; raw capture; ISO 3200
Exposures: Luminance and Ha: 3 hrs. each for six panels (2x3)
Color: average of one hour for each panel
Processing: L and Ha component images were obtained and processed with CCDSoft. Color images were obtained and processed in ImagesPlus. The panels were registered using RegiStar and the mosaic was created in Photoshop. A primary Luminance layer was created by blending the L and Ha composite images. This was combined with the color layer to produce the final image.
Details: Imaging took place from my backyard observatory in southeastern Minnesota. Dates ranged between mid-September of 2017 and early January of 2018.
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