Image sizes

Hi, I’m not sure if this is the correct forum but maybe someone can help. I’m using a Zwo 1600 mm cool with a skywatcher 200p. When I open my images in pixinsight, the size of my lights and darks are 2328 x 1760 while my flats and bias are 4656 x 3520. Because of this I cannot calibrate them. I’ll try the Pixinsight forum as well but I’m guessing they’ll say, “it’s a SGpro problem”!!!
Any help would be wonderful.
Kind regards,

You are binning your lights and darks somehow. You need to bin your flats also.

Does SGP have ROI features? If it is not binning, you much check to see if you are using an ROI…

Thanks Joel, yes, you’re right. I should have known and checked.

Thanks Jon, yes, it’s the binning, Doh!

You can bin your flats and bias files in Pixinsight rather than recreating them.

Well, never knew. These programs throw up so many surprises, and all good. Thanks DS.

If this were a CCD that would not be the best approach as the on-chip binning behaves differently to image processing averaging. I know CMOS cameras bin differently to CCDs but the details change with the chip implementation. In the case of this camera, is the binning operation during acquisition identical to image processing binning in terms of signal and sensor noise contributions? I’m wondering if it treats the the fixed pattern noise, gain and read noise similarly.

Whoa, that’s getting complicated. I’ll give it a try and if it’s no good I’ll have to get a new set of Ha lights. Thanks Buzz,

Phil - the more usual advice is to take all your calibration images with the same settings as you use for imaging. You can try what was suggested, only that it might not give the optimum results. If you are just starting out, PixInsight may be something for later on too. It is a wonderful application but quite daunting to begin with.

@buzz The 1600 can do two types of binning and we don’t know which was used here. In either case, the binning is basically addition which is what Pixinsight is doing. Won’t claim that it is identical, but it beats having to redo it.

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Finally got it sorted. Now I have to hope that it actually uploads…

Nice - I bet you are pleased with that.

Thanks Buzz, yes I am. It never ceases to amaze me what this digital revolution has done. When I was a child, photo images like that were only dreamt of by astronomers with access to huge telescopes.
Kind regards,

Aye!! Digital imaging has really gone quite far. It just keeps getting better, too. The ease and low cost of getting into cooled mono cameras with narrow band filters and the like, now, is amazing.

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