A Labour of Love – Shooting the Andromeda Galaxy

One of the first deep space objects (DSO) that astrophotographers tend to shoot, depending on the time of year, is the magnificent Andromeda Galaxy, Messier 31, and I’m no different.

Being one of our closest intergalactic neighbours, at only 2.5 million light years distance, it has a high magnitude, and is one of the largest objects in the night sky, having an area greater than that of the full moon if we were able to see it clearly with the naked eye.

Being so large it comes with its own set of issues, and you need to choose a setup that will allow you to capture all of its beauty in the field of view. For me, this would be the SkyWatcher 72ED and the modded Canon 450D.

I’ve imaged M31 several times previously and it doesn’t take a lot of data to capture something pretty awesome.

Captured with the 72ED and Canon 450D, this is 13800 seconds in January 2019 from my kids Class 5 skies.

The above image was my first real attempt at M31 and was taken across a couple of nights at ISO 800. The processing has been stretched pretty aggressively in order to bring out some of the detail in the dust lanes, which I feel has compromised the image itself. To me it looks pretty rough, and the over processing has brought out lots of faults in the data. The finer detail in the leading edge is missing because I’ve brought up the clarity and dropped the dark level down too far. The problem was that bringing the dark level back up brought out even more flaws. In order to decrease the number of stars I came down on the texture and sharpness, so the overall effect on the galaxy as a whole has given it a softer look, even with the bumped up clarity in the midtones.

Unfortunately the weather last year didn’t lend itself too well to astrophotography, and by the time it had cleared sufficiently, M31 was behind trees at my location. So I’ve had to wait until this year to have another go. Instead of starting from scratch though, what I’ve done is to add more data to what I’d already collated. One thing that you can never have enough of is data and time on target.

This has the benefit of increasing the SNR (signal to noise ratio), which means any stretching of the data in post processing doesn’t need to be as aggressive. Shooting a decent set of calibration frames each time you get in an imaging session as well helps to improve this further. You can also be a bit more discerning about the frames you keep. All of this can help to add to produce a better image, one that you can rightly be proud of.

M31. 4 hours of data across several nights, including the Jan 2019 dataset.

The second image includes last year’s set of data, and I think demonstrates why it’s a bad idea to get rid of the older stuff, especially if you keep the same equipment. This image is a lot better, and to my mind a lot more natural-looking. The stars are a lot tighter and I’ve also altered my processing techniques considerably from last year. I think the overall look of this version is a lot cleaner, with better and more controlled enhancements of the important areas of the galaxy disc.

As we come into late Summer / early Autumn, Andromeda is rising higher earlier, and this is being further helped with the nights becoming longer again and the welcome return of full astronomical darkness. This means that, weather permitting (which it hasn’t done for the last month at the time of writing this) I’ll be able to get some significant time in on this beautiful galaxy.

Update 110920

Managed to get out Wednesday night and add another 90 minutes of data which I’m currently in the process of adding into the mix. Think that brings it up to around 6 hours total integration time to date on this one.

Just managed to process my total data so far and it’s up to 6hrs 24mins of integration time, plus a complete set of calibration frames for each session. Loving how each time I add more to it I need to not be so aggressive with the processing.

6hrs 24mins with the modded 450D. This is 364 individual “sub” frames, and includes both 1 min and 2 mins subs

Update 260920

Managed to get out for another session on Andromeda a couple of night’s ago,and even though the forecast was for perfectly clear skies, they were anything but! Out of 6 hours worth of time spent actually imaging it, I managed to obtain a mere 48 more minutes worth of usable data. This is pretty common in the UK sadly, but does help to demonstrate just how much patience and resilience you need in order to pursue this (at times) frustrating hobby.

On the positive side, I managed to guide for the first time using the Star Adventurer, and was easily managing 2 minute subs. This was with the same setup I’ve been using previously to image M31; the 72ED and Canon 450D. Guiding was done with a 9×50 and ZWO ASI120mm, the same guide solution I use on the EQ5 Pro and also with the 200 P-DS.

M31 Andromeda Galaxy. 6hrs 54 hrs total integration time. All done with the SkyWatcher Star Adventurer and modded Canon 450D

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