Flat-Field calibration can not be performed correctly

@msamazing Michael, the popup explains it all. APP is unable to find either a MasterBias or a MasterDarkFlat that matches your data (gain, temperature and offset).

Can you tell us more about what you're trying to do? What version of APP are you using? Are you using OSC (color) data or mono? Or are you trying to mix both in one go? Note that mixing OSC and mono data may is not (yet) possible. Also, what flat and darkflat/bias data did you load?

Thanks, Wouter

@wvreeven I took flats before I imaged and then did lights.  I used darks from another time but maybe the darks are my problem.  I used a FlatMaster for my flats so they should be automatically handled.  The lights were shot with a color camera using a narrowband filter.  Could the problem be that my darks used a different ISO or it a bigger problem than that?

Also, I am using version 1.083. 

@msamazing Can you give a more precise description of the calibration data? You only mention darks and flats. No bias nor dark flats. What are you using exactly?

Regarding the APP version: can you be more precise there as well? The latest and stable version of APP is 1.083-4 for Windows and 1.083-2 for macOS or Linux. Please make sure you have installed any of those versions because all other 1.083 versions have bugs in them.

@wvreeven To being with, I have to apologize as I had a "brain fart".  I completely forgot the bias files.  Dah.   It actually processed fine after that.  

When I look up the version I am running on my MAC, it only says:  Version 1.083 (1.083).  Does that mean there is a more current version I should install?

After processing my image, can I upload it and have you take a look to get some suggestions?  It is definitely on the green side.  There is no rush.

@msamazing No need to apologize. I am glad you managed to solve the issue.

Yes, there is a newer and stabler version 1.083-2 of APP for macOS. See the downloads section under your account. Please install that as it has several important stability improvements over the original 1.083.

Regarding the green color of your integration result, OSC data tends to have a green cast due to the double number of green pixels wrt red and blue. What narrowband filter do you use? Does enabling background neutralization reduce the green cast?

@wvreeven I used a color camera with the Radian Triad Ultra Narrowband Filter.  When I put a check mark in the neutralize-BG, it made the nebula lighter and everything was a little more green.  do you want to see the file?

@msamazing What settings did you use in tab 0? Did you use the default settings or change to one of the Ha-OIII settings? The answer to this following question probably is yes, but to be absolutely sure: did you create flats using the filter? What do the lights look like? Are they green as well? And the raw flats? Green as well?

@wvreeven I used the default setting in tab 0.  I did create flats for the filter.  The lights look more gray.  The flats are green. Do you want to look at the final result?

@msamazing No, I'd prefer to have a look at the raw lights and calibration data. Can you upload 5 of each to

@wvreeven ok i uploaded the files.  Thank you.

@msamazing Thanks a lot. Unfortunately it's impossible for me to download them from the airport. However, can you please either rename the files so it is clear from the filename which is which OR place them in sub-directories indicating their type?

@wvreeven Done.  I put them in sub folders.

@wvreeven Hello, I am curious if you were able to view my files.  

@msamazing I had a transatlantic flight and just arrived. Hopefully tomorrow I can have a look. 

@wvreeven there is no rush thank you.

@msamazing OK I had a look at your data. The lights certainly don't look grey but have, as expected, a green hue. They look perfectly normal to me.

The flats, however, look way too green. Also note in the histogram that there is no red signal apart from a few hot pixels that manifest themselves as little red spikes at the bottom of the histogram.

I noted that there is no offset recorded in the FITS headers which seems to be something that NINA may wish to change.

In any case, the issue are the flats. What light source did you use for them? It looks like it may be too bright in the green section of the spectrum and barely emitting light in the far red (Ha and SII are around 650 nm).

HTH, Wouter

@wvreeven I was using the Pegasus Flat Master.  NINA is supposed to do the calculation.  Not sure what went wrong.  This is very helpful and very much appreciated...

@wvreeven I was using the Pegasus Flat Master.  NINA is supposed to do the calculation.  Not sure what went wrong.  This is very helpful and very much appreciated...

@msamazing Not sure what may be going on then. Is it possible for you to use a different light source? Perhaps the sky during the day (cloudy or blue) while covering the front of the telescope with one or more layers of white t-shirt or towel? I usually point my t-shirt-covered telescope at a white wall or door. If you give this a try then you might be able to see if that makes a difference.

@wvreeven I will try that.  In the past the NINA Flat wizard worked so I am not sure what happened.  Is it possible to salvage this with APP or not really?

@msamazing I don't think it is the flat wizard but the combination of the flat panel with the filter. Did you successfully create flats with the panel and the filter in the past?

Since there is no (or barely any) signal in the red channel in the flats and since the filter lets pass through a LOT of red, APP or any other image processing application can do anything here. You can try to process the data without the flats and see if the result is usable but I am afraid that that may not be the case. Still, if there aren't too many dust devils in the lights, you can try to connect the camera and filter again and take new flats. You never know if those will get the job done. Again, no guarantees unfortunately.

@wvreeven I took the flat the same night as the lights. I also used the same filter.  I will just try again and see what happens.  Thanks again!!!!