Clouds of Andromeda

A deep integration time on a wide field image of Andromeda Galaxy (M31), using an Ha filter, shows an amazing view that has been recently called the Clouds of Andromeda. A faint structure of Galactic Cirrus, part of our Milky Way. The image covers a diagonal that could fit 38 full moons inside.

As soon as I saw Rogelio’s Bernal 2017 image of Andromeda (see the APOD here) I knew I wanted to get such a deep view of this area. As the time went by more images appeared, most of them showing a detailed (crop) view. This 2021 I acquired a new widefield astrophotography setup specially designed for this project. It consists of a regular DSLR lens (a Sigma Art 85mm) and a new CMOS camera matched with a full set of filters.

As I started integrating the data in the Ha channel (3nm Ha narrow band filter) some really faint clouds appeared. But it was not until I got around 30h of data that it was possible to do a full processing of this image showing the faint Galactic Cirrus that surrounds this area of the night sky. I captured all the Ha data stopping the lens at f/2.8. But the star shapes were not good enough, so I combined the RGB image of the stars captured at f/4.0 (thanks Daniel for this great idea).

My interest in Galactic Cirri started several years ago when I started my collaboration with the Instituto de Astrofísica de Canarias (Drs. I.Trujillo and R.Infante) in a low surface brightness study of the M101 Galaxy. You can see this project here: https://astrocat.info/pro-am-science/

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Image Details

L: 35×300″ f/2.8
RGB: (33;43;45) x 300″ f/2.8

Ha: 217×600″ f/2.8

RGB: (12;10;12)x300″ f/4

All images at 100Gain -10ºC bin12
Calibrated with 30 flats (part of the data), 30 darks, 30 dark-flats

Average darkness: 21 mag/arcsec2

Image resolution: 9.12”/pixel

Image dimensions: 15º50′ x 10º35′ – Diagonal 19º (38 full moons)

Data acquisition: September and October 2021

Ha exposure: 36h10′

Total exposure: 52h

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Equipment

Sigma Art 85mm 1.4

Mesu200 mount

ASI2600MM Pro camera with ZWO EFW 7 pos

Guiding with ASI120MM and ZWO Mini Guide Scope

Astrodon LRGB filters & Antlia 3nm Ha Pro filter

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Software

SGP, PHD2, APP, PIX, LR, PS, TPZ.

Aleix Roig, October 2021.
Prades (Tarragona, Catalonia – Spain).

Full HD view available on Astrobin: https://www.astrobin.com/hjyu5b/

Video animation: https://youtu.be/lo5oeTtuF60

See this other version of this work with an airplane crossing the field just across the center of M31 core: https://astrocat.info/clouds-of-andromeda-as-a-bulls-eye/

Download ORIGINAL HD