M31 – Andromeda (LRGB)

M31 – Andromeda (LRGB)


M31. Andromeda. Every astronomer and most non-astronomers know this galaxy. It is the galaxy that is closest to our own with barely 2.5 million light years distance. At a whopping 3.167×1 degrees Andromeda is the largest galaxy visible in our night sky and the largest DSO that is not in our own galaxy as well. Andromeda is a spiral galaxy in the name-giving constellation of Andromeda. In dark enough skies the nucleus of M31 can be easily seen by eye even without a telescope and with a telescope it can even be seen from light polluted skies with its surface brightness of 22.3 SQM.

Andromeda is a very typical Sc type galaxy with very tight spiral arms hugging the nucleus of the galaxy itself. It features many dark dust lanes separating the spirals visually. With the large size of Andromeda it is even possible to make out very large scale DSO inside the galaxy itself. I will provide an image that has those DSO marked in the Annotated Image section. Sadly not all HII regions inside the spiral arms are visible as such, it was really difficult to get the color for this image out properly.

The sister galaxies M32 and M110 are also visible on this image. Both of those galaxies are rather small elliptical galaxies and are considered satellites of Andromeda. M110 does show faint core detail with minor dark dust bands near the nucleus. Either of those galaxies interact with Andromeda itself, for M110 you can even see the faint band of stars linking Andromeda and M110. M32 as the physically smaller dwarf elliptical galaxy has a bit more interesting interaction with Andromeda. With the current state of information thanks to X-ray telescopes it shows that it punched through the spiral arm of Andromeda itself.

Technical Details

Woo! The first successful and properly made LRGB image with just the 383L+ for a while. The RGB dataset even was shot with my new DIY motor focus and that worked out great. I am super pleased with the detail in the galaxy and how the exposure captured a lot of the surrounding halo of the galaxy itself. I cannot say much more about all of that, everything went exactly as expected and predicted. The setup with just the 420mm scope is very easy to use and very reliable.

Acquisition Details

Shot with Atik 383L+ on TS Optics 70mm f/6 APO FPL53 Triplet

Date: 2018-09-10 & 2018-10-10
L: 75×240s 1×1 binned
RGB: 30×240s 1×1 binned each

Postprocessing Details

Will follow

Annotated Image

M31 – Andromeda (LRGB, Annotated)

Full annotation including DSO inside Andromeda will follow

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