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flat frame not being applied  

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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 28, 2021 23:40  

@wvreeven

 

So are you say you run the process one at a time for L then R then G then B and that worked but when running LRGB all in one process it did not work. I am correct i think thats what you indicated

Problem doing that would be it would not register the frames so they are stacked correctly

So if this is the problem a fix from Mabula would be great and a temp workaround if you can give me one, have load of nights of images i would love to process.

 

Mike


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(@wvreeven)
Quasar Admin
Joined: 3 years ago
Posts: 1110
July 28, 2021 23:41  
Posted by: @moviecells

So to be sure how did you get the good final integrated images they look great want to try here.

Load only the lights, flats and dark flats of L together with the master dark and integrate. Then repeat that for B, G and R.


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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 28, 2021 23:43  

@wvreeven

 

You put

some reason people think that the peak should be in the middle. And apparently this is what NINA tries to aim for as well. However, when the peak is much further to the right (without saturating any pixels) then a larger dynamic range of the sensor is used leading to much better correction.

 

So for the flats do you mean shift the ADU up so the peak is higher.

 

Mike


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(@wvreeven)
Quasar Admin
Joined: 3 years ago
Posts: 1110
July 28, 2021 23:43  
Posted by: @moviecells

Problem doing that would be it would not register the frames so they are stacked correctly

Once you have the four integration results then you can load those four as lights. APP will indicate that they already were processed and will ask if you are sure. Yes, you are sure. Then go to tab 4 and click the Register button. Once done, click the Save Registered Frames button and then you can channel combine them.


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(@wvreeven)
Quasar Admin
Joined: 3 years ago
Posts: 1110
July 28, 2021 23:43  
Posted by: @moviecells

So for the flats do you mean shift the ADU up so the peak is higher.

Exactly.


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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 29, 2021 10:53  

@wvreeven

 

Thanks for the work around for now but there will be a fix correct this is lot more work doing it this way i normal just load all the file and start it going on multiple night images it can take a good few hours to process. 

Having just paid for a full version and upgraded from yearly version only a few weeks ago feel a little let down.

If this is not working for me how are other people not having a problem, is there another way to do all this so i can load all the files and get good results.

Mike


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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 29, 2021 11:13  

@wvreeven

 

Hi it did not work i loading just Lum light, Lum flats, Lum darkflats and master dark and integrated but got this below still major problems. I got no error but this was the result not sure how your integrated looked just fine

 

m101 meade Luminance St

if i switch the view options i can't see any difference from linear,image and calibrated they all look the same its like there is no correction applied. i saved a copy of the log if you need it

 

This post was modified 2 months ago by Michael Purver

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(@mabula-admin)
Universe Admin
Joined: 4 years ago
Posts: 2692
July 29, 2021 11:47  
Posted by: @wvreeven

@moviecells Mike, when I load the lights, flats and dark flats in APP 1.083-beta2 I get the following warning:

Screenshot 2021 07 27 at 17.52.01

The reason for this warning is that you have created dark flats for each flat exposure time and then try to integrate those per channel to create master dark flats for each of L, R, G and B. Apparently some of the exposure times do not agree which is why the popup is shown.

The correct way of doing is is to shoot one set of dark flats of for instance one second and then also shoot a large set of bias frames of 0.01 second. Then create a master bias and use that together with the dark flats to create a master dark flat. Those two together can then be used to properly calibrate the flats and create the master flats for each channel. Can you give that a try?

Hi @moviecells & @wvreeven,

The warning in this case is caused by the missing MasterDark for the light frame calibration. If there is no MasterBias or no MasterDark, Flat-Field calibration can never work because the sensor offset will not be removed from the light frames.

Mabula

 

This post was modified 2 months ago by Mabula-Admin

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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 29, 2021 12:16  

@mabula and Wouter

I am getting more and more confused here.

I supplied files for flats and matching darkflats, light frames and a master dark. So how can it be missing. Wouter did you load the master dark when you had this error can you contact madula

More important is i don't see any errors my end and i still don't get calibrated images.

Wouter seems to think there is a bug when i load all my lights and process them all in one go so asked me to process them one at a time but i can't get it to work.

Could you talk to wouter not sure what going on and try and figure out the bug and also why i can't reproduce the method of doing one colour at a time as i tried L but get same uncalibrated image.

having just spent money out for a owners version all i want to do is process my images and get a good result

 

Mike

 

This post was modified 2 months ago by Michael Purver

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(@mabula-admin)
Universe Admin
Joined: 4 years ago
Posts: 2692
July 29, 2021 12:18  

Hi @moviecells & @wvreeven,

I have checked the data, I integrated Lum,R,G,B in one go and get the same results as you, which are not good, especially the L-channel shows severe ringing.

If I process only the L data from scratch I get the exact same result as processing L,R,G,B from scratch, so in that sense I don't see a bug here in how APP calibrates the data by applying the different masters to the light frames.

The Luminance integration from the L,R,G,B processing, notice the wider field of fiew of the integration because it is registered for the whole data set:

m101 Luminance session 1 St

The Luminance integration from only processing the Lum data, looks exactly the same with the same auto stretch (30% BG, 2sigma):

m101 onlyL Luminance session 1 St

The L-calibrated image viewer per light shows the same problem. Michael, double click on 1 of the light frames in the frame list, set the image viewer to Linear and you see the uncalibrated raw data of the light frame:

Uncalibrated Lum frame

Then set the image viewer to L-calibrated with the drop-down box above the image viewer and you will see the calibrated light frame where the masters that are assigned to the light frame are used. The masters that are assigned are shown in the frame column below the image viewer:

calibrated Lum frame

Since this is only 1 light frame, it is harder to see the ringing appear when compared to an integration of 5 of these light frames. But by further manually stretching, you see it clearly. I manually increased the stretch by lowering the ST slider and increased the Black Point by increasing the B-slider (Make sure the slider is set to 3-4 zoom level, so you can do this easily 😉 ):

calibrated Lum frame extreme stretching

So at first glance, i don't see any indication of a problem in APP's calibration module. I suspect the problem to be either:

  • that the MasterDark is only 16bits, we can check easily if this is the problem if Michael creates a new 32bits MasterDark using the the same temperature, sensor gain + offset  as was used in creating this 16bits MasterDark. We do know that for these newer CMOS camera's 32bits masters are needed 😉 so there is a good change that this is our problem.
  • The flats are simply not shot correctly, this can be due to light leakage or the method that was used to create the flats.

Mabula

 

 


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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 29, 2021 12:21  

@mabula-admin

How did  Wouter get better results he sent me some processed lights and they looked good much better than mine or these see post on page 4

 

Mike


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(@mabula-admin)
Universe Admin
Joined: 4 years ago
Posts: 2692
July 29, 2021 12:21  
Posted by: @moviecells

@mabula and Wouter

I am getting more and more confused here.

I supplied files for flats and matching darkflats, light frames and a master dark. So how can it be missing. Wouter did you load the master dark when you had this error can you contact madula

More important is i don't see any errors my end and i still don't get calibrated images.

Wouter seems to think there is a bug when i load all my lights and process them all in one go so asked me to process them one at a time but i can't get it to work.

Could you talk to wouter not sure what going on and try and figure out the bug and also why i can't reproduce the method of doing one colour at a time as i tried L but get same uncalibrated image.

having just spent money out for a owners version all i want to do is process my images and get a good result

 

Mike

 

Hi Michael, in the post of Wouter where he got that warning, he did not load the MasterDark 😉 If the MasterDark is loaded, the warning will not show. So this is normal and correct.

Mabula

 


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(@mabula-admin)
Universe Admin
Joined: 4 years ago
Posts: 2692
July 29, 2021 12:25  

@mabula-admin

How did Wouter get better results he sent me some processed lights and they looked good much better than mine or these see post on page 4

 

Mike

 
Posted by: @wvreeven

In any case, it looks like you have discovered a bug in APP. When I only load the lights, flats and dark flats for L and the master dark and then integrate those I get a nearly perfectly corrected image:

Screenshot 2021 07 28 at 17.06.48

The same for, respectively, Blue, Green and Red:

Screenshot 2021 07 28 at 17.07.03
Screenshot 2021 07 28 at 17.07.19
Screenshot 2021 07 28 at 17.07.40

The final artifacts you probably can eliminate by making sure that the peak of the histogram of the flats is much further to the right. For some reason people think that the peak should be in the middle. And apparently this is what NINA tries to aim for as well. However, when the peak is much further to the right (without saturating any pixels) then a larger dynamic range of the sensor is used leading to much better correction.

I suspect that the bug is related to the fact that you have dark flats with different exposure times and it look like those do not get applied correctly to the flats. But I may be wrong and this is for Mabula to investigate. Thanks very much for your patience and for answering all of our questions!

Hi Wouter @wvreeven and Michael @moviecells,

On my computer monitor I still see the ringing in the L-data, the images posted are also weakly stretched so it is hard to see, but I see it, so I expect the results are the same and not good. Like I mentioned, If I process the L data only, i get the same result as processing L,R,G,B combined, so I don't see a bug and have no clue how you could get a different result.

Mabula

This post was modified 2 months ago by Mabula-Admin

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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 29, 2021 12:26  

@mabula-admin

Hi I made my masterdark with APP back when i took them, my master dark i have upload for Wouter with my files it looks to be 50mb in size so may be a 16 bit file as the final integrated images are 32 bit and 125mb in size. I can try and make a new master dark.

 

I don't think from the test i have done and i have used different flat method there is a ligh leak.

 

Mike


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(@mabula-admin)
Universe Admin
Joined: 4 years ago
Posts: 2692
July 29, 2021 12:30  
Posted by: @moviecells

@mabula-admin

Hi I made my masterdark with APP back when i took them, my master dark i have upload for Wouter with my files it looks to be 50mb in size so may be a 16 bit file as the final integrated images are 32 bit and 125mb in size. I can try and make a new master dark.

 

I don't think from the test i have done and i have used different flat method there is a ligh leak.

 

Mike

Hi Michael @moviecells

Okay, let us first rule out that the masterdark is in fact the issue. So please make just a couple of darks (8 would be enough) with the same temperature, exposure time, and sensor gain + offset.  Then create a new MasterDark of 32bits 😉 and reprocess with this new MasterDark 😉

Chances are good that this is the issue. I have seen from another APP user that this caused the ringing issue on these new camera's. 16bits masters are not good enough it seems for these sensor's to get optimal calibration.

Mabula

 


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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 29, 2021 12:38  

@mabula-admin

 

Ok made a new masterdark i have uploaded to the folder if you want to try i will run it too. By luck i keep all my camera images so it was just a case of re processing them to 32 bit and not having to retake any

 

Mike

This post was modified 2 months ago by Michael Purver

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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 29, 2021 12:55  

@mabula-admin

Well to me results look the same see below could you run it too. What about using all 16 bit master ?

32 bit Luminance St

mike


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(@mabula-admin)
Universe Admin
Joined: 4 years ago
Posts: 2692
July 29, 2021 13:07  

Hi Mike @moviecells,

Indeed, I see no difference with the 32bits MasterDark. 16bits processing will never make it better for sure.

This leaves me to conclude that the issue is in fact in the flats themselves when compared to the light frames... somehow the illumination profile in the flats don't match with lights then and this can have many causes. I will study the frames in a bit more detail if I can see what is going on...

Mabula


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(@mabula-admin)
Universe Admin
Joined: 4 years ago
Posts: 2692
July 29, 2021 14:06  

Hi Mike @moviecells,

Okay, I have now studied the flats in more detail to find out of the illumination profiles are logical between the different filters. If they are logical, you expect that if you, for instance divide the Red MasterFlat by the Luminance MasterFlat, that you get a flat surface showing only the dust spots difference between the 2 filters. If they are not logical, it means that there is a problem in the flats themselves.

The illumination profiles between the L, R,G,B filter data should almost be identical leading to flat fields when you load a certain masterflat as light and apply another masterflat as masterflat in calibration.

Now if there is a problem in

  • how the flats are created or
  • light leakage in the optical train

 

this test should show it normally.

This is what I get when I load the Red masterflat as a light and use the luminance masterflat as a masterflat. First the masterflat is shown, then the division by the other MasterFlat. Please note, the multi-channel and multi-session functionality is disabled to perform this test. auto-detect Masters and Integration in 1)Load is also disabled.

Red MasterFlat
Red MasterFlat by Luminance MasterFlat

This is what I get when I load the Red masterflat as a light and use the luminance masterflat as a masterflat.First the masterflat is shown, then the division by the other MasterFlat.

Green MasterFlat
Green MasterFlat by Luminance MasterFlat

This is what I get when I load the Blue masterflat as a light and use the luminance masterflat as a masterflat.First the masterflat is shown, then the division by the other MasterFlat.

Blue MasterFlat
Blue MasterFlat by Luminance MasterFlat

You can clearly see that there is no consistency between the divisions. The R/L results is opposite to B/L which is an idication of a tilting filterwheel perhaps. See depening on how the telescope is aimed, the filters are never orthogonal to the direction of incoming light and always off with a certain angle.

Final 3 checks: 

R divided by R, should give perfect flat result which it does:

Red MasterFlat by Red MasterFlat

G divided by R:

Green MasterFlat by Red MasterFlat

B divided by R:

Blue MasterFlat by Red MasterFlat

We clearly see not-logical illumination profiles between the masterflats, which for me is hard evidence that the issues are caused by

  • a problem in how the flats are created
  • or a problem with the optical train like a light leakage or a tilting filterwheel.

I would not be surprised now if the issue is in fact the filterwheel. Can you check internally if the filterwheel will wobble depending on how the telescope is aimed?

Mabula

This post was modified 2 months ago 2 times by Mabula-Admin

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(@moviecells)
Red Giant Customer
Joined: 1 year ago
Posts: 87
July 29, 2021 15:11  

@mabula-admin

 

If you can it will help i have tried both my light box flats and also sky flats both with same results. I tried Wouter checks for any IR light and used a 4 watt IR torch and can find no light leak for IR and also my dark flats even the 40 second exposure of narrow band filters taken during the day show no hint of a light leak so am at a loss of what the issue could be.

 

Mike


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