When I calibrate the Flats, I only use the master bias and not the uncalibrated master dark as well.is that correct? I have my master bias that I will only use to calibrate my flats. So I have my un-calibrated master dark with no optimization. Just to be clear on two final points for processing with this camera. Use only those two to calibrate each light. So now you have a master dark and a master flat.

Calibrate the flats with the master bias and then integrate the flats to create a calibrated master flat. I assume that what I'm doing is 100% correct, but if anyone sees a flaw in this please let me know!Įdited by rjbokleman, 16 December 2016 - 01:56 PM. I then calibrate these Flats with the MasterBias as noted in Kayron's tutorial: to generate a set of Master Flats per filter for this particular target. I then create a complete set of Flats for the specific target which takes into account, focus point, gain/offset, and filter. So my MasterDark(s) have all been calibrated with my MasterBias to actually create and stack the final MasterBias for each exposure time, Gain/Offset. ' First of all however, we will calibrate our individual dark frames with the master superbias in order to remove the sensor bias signal from each dark frame and thus make our master dark be representative purely of the dark current signal produced by the camera during the exposures.' I then use Kayron's wonderful tutorial(s) for creating the MasterBias and MasterDark(s). So for the 30' exposure, I'll stack 240 Darks, on the 300' exposures I'll only stack 24.

Usually the number of exposures taken for each of these gives me at least two (~2) hours stacked. I'm using MasterDark(s) for each and every exact exposure length (30', 60', 120', 150', 180', 240', 300') and Gain/Offset values ( not a single long 300' exposed dark scaled down by PixInsight) in SGP. I use a single Bias taken at 0' in SGP based only on Gain/Offset/Driver version changes, so I have two MasterBias at the moment G139/O21 and G75/O12 consisting of 100 frames each, but I do not create or use a SuperBias out of these. (<-I'm sure I'll get corrected on that point if I'm wrong.) That effectively leaves behind a darker 'ghost' of the glow, if it's strong enough in the flat.Īs Jon has mentioned a few times, in other threads, I dropped the SuperBias process from my routine when I switched to the ASI1600MM-C.īoth Warren Keller (Inside PixInsight) and Kayron Mercieca (Light Vortex Astronomy) are advocates of the SuperBias, but I think this point of view is perhaps more relevant for CCDs than the CMOS ASI1600MM-C. If there are strong enough glows in the flat, you should see some darkening in the areas where the glows are, since division of the flat will brighten the light where the flat is darker more than it will brighten the light where the flat is brighter. Then divide the flat from the light with PM with Light / Flat. Subtract the dark from the light in PM with light_frame + mean(dark_frame) - dark_frame, and name that 'Light'.

Subtract the bias from the flat in PM with flat_frame - bias_frame, and name that image 'Flat'. I like to use PixelMath in PI to do a quick and dirty calibration. However I've seen people who have significantly more glow with just 5 second subs. In my case, I don't really see much glow until 20 seconds or so, and then it is only about 1e- (which is usually just a few ADU). I have noticed that the glows do not seem to be consistent from camera to camera. I am not sure there is a simple answer to that question. I don't do the dark scaling/optimization so will only use a master dark to am using Flats so will do as you suggest above and end up using only a Master Dark and Master Flat to calibrate the Lights. That would be used to calibrate the flats in lieu of a master bias. You might be thinking of flat darks? If you are having to use longer exposure flats (might be the case with narrow band filters), then you might want to consider using a flat dark frames to create a master flat dark, just to make sure that you are correcting any amp glow in the flats. I don't use a bias when calibrating my lights. However, once I have the master flat, I calibrate the lights with only the master dark and master flat. Now, when I calibrate my flats, which are usually less than 1 second exposures, I will use a master bias to calibrate the flats. For a lot of my narrow band stuff, I only use a master dark. A master dark contains the bias, so just the one master is sufficient. If you aren't using flat calibration, and are not doing dark scaling/dark optimization (and you should NOT be with this camera), then all you need is a master dark to calibrate the lights. Hmm, not sure where the dark master thing is coming from.

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