Androm-again – And Is She Stacked!

19-10-24 stacked M31-cropped

I am pretty pleased with this result.  Eleven images 60 seconds each at f/3.5 ISO 800 shot at 50mm and cropped.  Processed with pixinsight using guidance from Alan Hall’s book. After stacking with pixinsight The image had a greenish tint and I eliminated that by using the color slider in the windows photo tool, then used the brightness slider to reduce brightness a bit.  That’s a crude tool but i’m happy with the result.

Above M31 you can see M110 and the greyer “star” below it is M32.  The two brighter stars  midframe are v Andromeda and 32 Andromeda.  Near the bottom center us u Andromeda.

Below, for reference is IMG_3963, one of the 11 frames stacked to generate the picture in its original size and roughly cropped to match the above.

I now have a 135mm lens which I intend to try on the next good evening.  Assuming I can do 60 second exposures I would need higher ISO to get the same brightness because the lens is f/5.6 rather than the 3.5 I was using for the above.  According to this I think the brightness ratio is (5.6/3.5)^2 or about 2.5 so I will try ISO 1600 for 75 sec and if that’s no good, ISO 3200 for 37 sec.


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