cuivenion Posted May 11, 2016 Share Posted May 11, 2016 Hi, I'm using a GPCAM colour to take DSO images. I'm wondering how to set the gain. For my first couple of attempts I've used maximum gain in order to make sure that I picked something up, but I'm wondering if this is the best way to go about it. How do you think I should go about setting the gain on this cam in order to get the best signal to noise ratio? Here's a couple of links to my first attempts with this cam: Link to comment Share on other sites More sharing options...
cuivenion Posted May 12, 2016 Author Share Posted May 12, 2016 Put this up quite late so I'll give it a cheeky bump. Link to comment Share on other sites More sharing options...
cjdawson Posted May 12, 2016 Share Posted May 12, 2016 I think your gain is fine where it is. No harm in lowering it a bit if you want. But by far the most important thing is take more sub frames and stack them. When you get into it, you'll be wanting to take sets of lights, darks, flats and bias. All work together to bring more signal. Link to comment Share on other sites More sharing options...
cuivenion Posted May 12, 2016 Author Share Posted May 12, 2016 5 minutes ago, cjdawson said: I think your gain is fine where it is. No harm in lowering it a bit if you want. But by far the most important thing is take more sub frames and stack them. When you get into it, you'll be wanting to take sets of lights, darks, flats and bias. All work together to bring more signal. Thanks for the reply, I think for the fainter targets max gain will be fine But I'll drop it for bright globs like M13. I tried a couple of test shots with a 50mm guide scope and M13 seemed to have it core blown out at max gain. Link to comment Share on other sites More sharing options...
cjdawson Posted May 12, 2016 Share Posted May 12, 2016 That sounds about right. The lower the gain, the lower the noise from the chip. Actually thinking about this, you could simply lower the gain for everything, then bring out the detail in post. The key thing is that you are capturing the raw data rather than a jpeg or other format that losses fidelity. I use a DSLR and image using Raw because the data in the raw file is the values that were read directly from the chip without any kind of processing. It means that when I import the raw file to photoshop, all the data is then bought into memory and I can stretch the image to bring out the detail. With Jpeg, the streching would stretch the jpeg artifacts and would degrade the image quicker. Link to comment Share on other sites More sharing options...
cuivenion Posted May 12, 2016 Author Share Posted May 12, 2016 Sounds like I have some experimenting to do. I capture in RAW, so I don't have to worry about that. I've been using darks, the light frames are very noisy without them. Link to comment Share on other sites More sharing options...
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