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M31 - With Difficulty


jgs001
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Bit of an experiment last night... apart from the oddity of it actually being clear... I used ISO400... The kit all worked very well and didn't take long to setup which is good.

17x6 mins @ISO400

11 flats

11 darks

bias frames

Not that the darks and bias really made much difference, I stacked with and without the end result was much the same... I didn't have enough data, that was the problem..

m31fullb.jpg

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Decreased the contrast, set the black point around to 2., adjusted the Histrogram, Unsharpen mask, also used Gxterminator. Used some curves & adjusted the Mid Tone, but not too much. Last thing was removed some digital camera noise. But you do need at least a few more hours of Data.

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as always there is a contrast problem with M31, very bright core and faint outer regions. The only solution is more exposure! Having said that this is good going for an hour and a half.

Darks contain the bias signal so if you are subtracting darks you don't need bias. Unless it was just to bias subtract your flats.

Nadeem, I'm not sure about your re-work. Your version looks too contrasty, probably because you lowered the black point too much. It should be around level 20-30.

Dennis

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Thanks Dennis, my original the black point was around 20-30. I don't know how DSS does it's dark, bias and flat subtraction, and whether the bias is only subtracted from the flats or not... Hopefully I'll get another clear night or two in the not too distant future...

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Nadeem, I'm not sure about your re-work. Your version looks too contrasty, probably because you lowered the black point too much. It should be around level 20-30.

Dennis

No problem, only trying to help. I quite like it, But then again it's not my image is it !

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