Taking Flats with SGP


#1

I have been having fun using SGP tonight, after being frustrated for the past week and a half. I still have bugs to figure out before I can do everything within SGP, but I do need some information.

In addition to taking some light frames, I also needed to take bias, flats and darks with my Canon 600D camera.

I did some math, and figured that my Bias needed .00025 second exposure.

I used the histogram to adjust my exposure time for Flats to .15 seconds. From what I have read, the peak in the histogram should be in the middle of the graph.

But I had a problem, and that was that when using BYEOS, my camera is set to the “AV” mode. But SGP did not recognize this setting. I ended up having to set to Manual (B) before SGP was happy. Is this correct, or am I missing something. What is the setting you use for taking Flats with SGP, Manual (B), or like with BYEOS, “AV”?

I guess for tonight’s data, I am hoping the "Manual (N) setting will be ok, especially since I stack everything with Derep Sky Stacker (DSS)

I will try again after I finish my Darks to redo the Flats via “AV” mode, now that I know the exposure time. Hopefully it was an exposure time problem.


#2

Three is a wonderfull module called flats calibration wizard. Just set the adu you want and it will find the ideal exposure time and apply that to a profile.

Then simply make a sequence with ‘flats’ as the type using that profile and SGP will put the proper exposure time in for you.

Easy as can be.


#3

I found the calibration wizard module, but those same “ADU” things told me I couldn’t use it because I haven’t a clue what ADU is, and how much of those apply for all my cameras. Though I looked it up, and it is supposed to be analog to digital units. I looked up the specifications for my Canon 7D mkII, and no where does it mention ADU’s

How do I determine the ADU for my Canon 600D, Canon 7D mkII, ZWO ASI 174MN Cool, and ZWO ASI 1600MM Cool caneras"


#4

Regardless of the CCD’s bit-depth… 12-bit, 14-bit, 16-bit or whatever, SGPro translates all image data to 16-bit. This means the histogram is representative of 65,536 ADUs. Like you said, shoot for something from 20,000 - 30,000 ADU for your cameras.


#5

Ken, Thanks so much. I will go with the middle to start, 25,000. I guess that if the histogram is to the left, I increase the figure, and vice versa. Like everything in this complex hobby, I will need to record these figures for every camera


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