Flats Calibration Wizard


#1

Hopefully a fairly easy change and quite possibly something I have simply not spoitted elsewhere but just in case, could the target mean be stored and persisted between sessions for the Flats Wizard? I keep forgetting to reset it to the value that matches my CCD especially as flats tend to beone of the last things I do to finish a nghts imaging so I am already barely thinking straight :wink: I don’t have a permanent system and often rotate the camera during framing so flats are something I have to do per target.

Regards
Ross


#2

Yes, we can do this. The reason we don’t is because the Flats Calibration Wizard is not designed to be run often. Are you running it a bunch? Since it’s inception, I have only run it once per new camera.


#3

Hi Ken, yes I do, I don’t have a permanent set up so need to set up and tear down at the end of each session, as well as rotating the camera to suit the target I am aiming for so I am often changing the camera/OTA alignment. My understanding is that flats are only valid if the CCD/OTA configuration have not changed from that used to take the image, so whilst I have master darks and bias I take a new set of flats each time.

Regards
Ross


#4

I pretty much do this also. I still don’t need to run the flats cal wizard more than a couple times a year maybe. While what you are saying about flat frames themselves is completely true (rotation and all that), the flats cal wizard is based on light collection. Unless your light source is very inconsistent, the time to achieve a certain mean ADU level should be fairly consistent (for the same camera with the same filter) regardless of camera orientation.

Maybe we are talking about different things… I am talking about the “Flats Calibration Wizard”. Is this what you are talking about or are you actually referring to the “Flats Wizard” that automatically generates sequences events for you?


#5

Hi Ken, I think we are talking about the same thing. My guess is its the nature of my setup. I find my home built light source for flats varies slightly with each use so after spending the night imaging, I do tend to play it safe and run the wizard once for each filter/bin used prior to taking flats. It could be me being over cautious running this but to me but clear nights are the exception in the UK, so I tend to play things as safe as possible. So my thoughts are that it makes sense for this setting to be ejther in the equipment profile (for multiple cameras) or at least persisted so the quality of flats is less dependant on someone remembering to enter the correct value time and time again (for running a few times a year, with my poor memory it still makes sense as it becomes more likely I would forget to change it). Then again it also highlights the fact I need to do something about the quality of my light source :smile:
regards
Ross


#6

This is my problem too. I have a light panel that is very tricky to reproduce the same brightness level, so I end up running the flats calibration wizard when I need to change the camera orientation, which often is also when I change targets. It’s rare that I can use the same flats for a long time across targets.

I actually have a flats “profile” that just utilizes just the camera and filter wheel while ignoring the mount and focus controller. This means that I avoid any potential hiccups like SGP asking for a guider when the sequence starts.


#7

OK. Well that’s interesting. If more people are doing this, we will also probably want to add behavior that makes the start exposure way closer to target for other binning level (instead of starting at 5 seconds for all runs). Response is linear for CCDs so if we know the exposure length for 1 binning we can predict way better starting points for the others. We haven’t ever done this because we never envisioned this tool as a “per session” behavior (or part of a regular workflow).


#8

A couple of things going on in this thread… I am actually prioritizing the effort to make the wizard faster by predicting subsequent exposure times for the same filter.


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