M 31, Andromeda Galaxy

About image

The Andromeda Galaxy, also classified as M31 in the Messier Catalog, is a spiral galaxy that is approximately 2.538 million light years from Earth in the direction of the Andromeda constellation, from which it takes its name. 

It is the closest large galaxy to ours, the Milky Way; it is also visible to the naked eye and is among the most distant objects visible without the aid of instruments as long as you observe from a sufficiently dark place.
M31 has a diameter that is about twice the size of our Milky Way (220000 light years against 100000). 

The red specks visible along the spiral arms are called HII regions, which means they are emission nebulae associated with young stars.

Technical data
Optic          TS Optics 76 EDPH - Aperture 76mm, focal lenght 342mm, f/4.5
Mount        Skywatcher EQ6R
Camera         ZWO ASI 294MM Pro with external filter wheel 7 positions
Filters         Antlia 36mm LRGB, Antlia 36mm Ha 3.5nm
Guiding system    Artesky Ultraguide 32mm
Exposure details     L 70x120" bin2 -15C

          R 40x120" bin2 -15C
                                    G 40x120" bin2 -15C
                                    B 40x120" bin2 -15C

          Ha 20x300" bin2 -15C

          Gain 120, offset 30 
Total integration  8h
Acquisition      Voyager, PHD2
Processing      Pixinsight 1.8, Photoshop CS5
SQM-L       21.14    
Location       Promiod (Aosta Valley, Italy)
Date           11 August, 5/6/7 November 2021

© Roberto Marinoni 2019 - All rights reserved