M31 Andromeda taken with SPC900NC

Posted by XTSee on 29th October , 2011

Here is my first attempt at imaging M31 The Andromeda Galaxy. At first glimpse you might think its a good picture, but I’m not actually that happy with it.

M31 Andromeda Galaxy taken with SPC900NC

M31 Andromeda Galaxy

Click the picture for a larger version, then hit Back when done.

Being a first try, I suppose it’s not too bad, but there are a couple of things wrong with the photograph, and it serves as a useful learning lesson for me.

The main thing is that M31 covers a huge area of the night sky, and because the SPC900NC has only a small chip size, it struggles when used on such large objects in the sky, and this was even with my f/3.3 Meade focal reducer to try and increase the field of view. In effect this is a photo of just the bright central core.

Next, is that my exposures were either not long enough, or that the camera settings (Gain, Gamma, Brightness/Contrast, etc), could have been tweaked while observing the Histogram graph in WxAstrocapture to improve the amount of data captured and hence get a better signal-to-noise ratio. Definitely many more images should have been captured and stacked.

When post-processing the image to remove the sky-glow, and using levels to improve the contrast, I have ended up removing too much detail. Really I should have referred to a pro image of M31 to compare how much sky area my image covered before starting the post-processing. By not doing so I have inadvertently cut-off the very faint halo of the galaxy around about the distance of where the first distinctive darker lanes of its spiral begin (this is where the outer edges of the core cut-off quite suddenly in my picture), and therefore none of the delicate halo shows from this point outward.

The image was created from 9 x 60 second exposures (plus darks, flat and bias frames) captured using WxAstrocapture (AVI), imported into K3CCDTools, then exported as individual frames in TIF format, then stacked, aligned and post-processed in Nebulosity, then the detail teased out using Photoshop.

I would like to have another go, perhaps trying to compose a mosaic to get more sky area, and definitely stacking more frames.

02/10/2011: 150mm C6-SGT with f/3.3 Meade Focal Reducer, SPC900NC/LX (640×480) and WxAstrocapture, unguided, K3CCDTools to TIF
9×60s lights, darks-bias, flats-bias, Nebulosity, Photoshop (Starspikes Pro plugin)

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