PixInsight WBPP and calibration frames

I wanted to keep this on the PI forums but my account still waiting for admin approval so here it goes.

I use PI and WBPP. as for calibration frames I use masters created from the ASAIR plus.

Is this okay to do? might not be ideal I know, but is there really anything wrong with it?

Also, I noticed yesterday while I was WBPP a new set of images, that my BIAS master was not considered as part of the registration/calibration files. Honestly this is the first time I notice it, and I've been using PI for about a month now, what could be the cause of it?

The BIAS master was processed in the same manner as all my FLATS and DARKS masters, taken with the ASAIR, stacked in the ASAIR and got a master from the ASAIR. None of the FLATS or DARKS seem to be having an issue as the BIAS.

Any recommendation?

Also,

Is there any difference from using Masters rather than a bunch of single DARKS,FLATS or BIAS?

Hi Alonso,
I am not an ASAIR user so I don't have direct experience to relate but in general with PI I think there could be issues trying to use previously integrated files from other sources. I have used master files in PI once I have created them in PI and that's not a problem but again I am doing everything in PI, not importing my masters. You might want to do that just to see if you get a different result, namely just take all the individual calibration files and process them in PI to get your masters.
HTH
Regards,
Dave

Oh my. Quite a few questions there.
First, I would recommend watching my series on WBPP. It will address many questions.
https://www.youtube.com/playlist?list=PLAzMa9eIVQkBmzPneF8hCgqwkrxsk7CDn

Secondly- I do not know if your other software uses normalized values. If the output is XISF files you will be fine. However, if not- you need to generate everything within PixInsight to save yourself from issues. If you are new to this... then you always want to minimize frustration right?

Your comment about the BIAS not being part of the "registration/calibration files" isn't something I can figure out. If the BIAS isn't being used correct (or you think so)- almost all answers to WBPP can be addressed by posting the screenshots of the panels (all of them). You can generate these screenshots with one button press using the "Diagnostics" button.

Yes, there is a difference between using masters and single Darks/Flats/Bias... a big difference in terms of noise and characterizing small electronic signatures that will impact your image quality at the end of the day.

I explain this an much more in my courses at AdamBlockStudios.com.

-adam

Hello

you can do what Adam suggest regarding the bias frame and actually let wbpp actually generate the master but the other alternative you can try is to use custom option at the bottom where you specify what the frame is an added in yourself you specify that it's a biased ring and that way there it should recognize it perfectly fine.

I wouldn't think using Master calibration frames created in Asiair would be a problem but Adam would know better than me as he is much more Master at pixInsight than I am. Adams video would probably show you that pixinsight uses header keywords to determine what type of files it's processing and if your keywords are not properly loaded in the headers then it's not going to know it's a bias frame and that's probably what happened.

Kevin

Alonso,

To answer your last question first: WBPP will always pick a master over single frames, provided the master(s) are appropriate for the Lights calibration.

About using "foreign" masters: others more experienced than me can comment on this. However, logically, master generation is a well understood process, so ASiair's method of generating masters probably produces masters that are quite compatible with WBPP/PI's masters. But as I said, I don't have any experience with this, being a solely PI user. If your calibrated master Light frame is without obvious artifacts, then it's a good bet that the masters you used were at least adequate.

BTW: Since you refer to BIAS frames, I presume that you are not generating Flat-Dark frames. I, personally, have stopped generating BIAS frames and always generate Flat-Darks as these automatically incorporate the BIAS component. If WBPP identifies Flat-Darks and/or a Flat-Dark master, then I believe it will ignore any loaded BIAS frames/master.

Regards,
Paul.

Paul Lloyd:
Alonso,

To answer your last question first: WBPP will always pick a master over single frames, provided the master(s) are appropriate for the Lights calibration.

About using "foreign" masters: others more experienced than me can comment on this. However, logically, master generation is a well understood process, so ASiair's method of generating masters probably produces masters that are quite compatible with WBPP/PI's masters. But as I said, I don't have any experience with this, being a solely PI user. If your calibrated master Light frame is without obvious artifacts, then it's a good bet that the masters you used were at least adequate.

BTW: Since you refer to BIAS frames, I presume that you are not generating Flat-Dark frames. I, personally, have stopped generating BIAS frames and always generate Flat-Darks as these automatically incorporate the BIAS component. If WBPP identifies Flat-Darks and/or a Flat-Dark master, then I believe it will ignore any loaded BIAS frames/master.

Regards,
Paul.

Yes, you are right Paul about the logic of dark frame matching. If there isn't a match dark frame, a bias will be used. If there isn't a bias or a matching dark...then the dark of the nearest time will be used.

The nicety of BIASes is that you can take just one and calibrate all Flats of any exposure time. For most sensors this works out perfectly. However, for sensors with Amp glow or other problematic electronic signatures... well then you need to match darks for any calibration of frames.

-adam

Adam Block:
Paul Lloyd:
Alonso,

To answer your last question first: WBPP will always pick a master over single frames, provided the master(s) are appropriate for the Lights calibration.

About using "foreign" masters: others more experienced than me can comment on this. However, logically, master generation is a well understood process, so ASiair's method of generating masters probably produces masters that are quite compatible with WBPP/PI's masters. But as I said, I don't have any experience with this, being a solely PI user. If your calibrated master Light frame is without obvious artifacts, then it's a good bet that the masters you used were at least adequate.

BTW: Since you refer to BIAS frames, I presume that you are not generating Flat-Dark frames. I, personally, have stopped generating BIAS frames and always generate Flat-Darks as these automatically incorporate the BIAS component. If WBPP identifies Flat-Darks and/or a Flat-Dark master, then I believe it will ignore any loaded BIAS frames/master.

Regards,
Paul.

Yes, you are right Paul about the logic of dark frame matching. If there isn't a match dark frame, a bias will be used. If there isn't a bias or a matching dark...then the dark of the nearest time will be used.

The nicety of BIASes is that you can take just one and calibrate all Flats of any exposure time. For most sensors this works out perfectly. However, for sensors with Amp glow or other problematic electronic signatures... well then you need to match darks for any calibration of frames.

-adam

Thanks for improving my knowledge on this topic, Adam. I'm still learning a lot after 2+ years at it! I guess it just doesn't stop. Most of my imaging is done with ASI183/294 which have noticeable lamp glow, so I've been using Flat-Dark frames.

Paul.

Lots of information to process here! Thank you so much everybody for your comments, I might be more confused now but I am going to get myself started on Adam’s video series, I guess that is my best bet right now.

Hi Alonso,
the Master Bias is not being used in light calibration unless the "optimize master dark" has been selected, see picture below to locate it in WBPP. This is because the bias signal is already included in the master dark, therefore the master bias in not necessary when they have the same exposure time.
The optimize master dark option is needed when light and darks have different exposure times, and optional otherwise.

Hope this helps.
Ciao, Mau

Hi Alonso,
the Master Bias is not being used in light calibration unless the "optimize master dark" has been selected, see picture below to locate it in WBPP. This is because the bias signal is already included in the master dark, therefore the master bias in not necessary when they have the same exposure time.
The optimize master dark option is needed when light and darks have different exposure times, and optional otherwise.

Hope this helps.
Ciao, Mau

Mau,

This post confuses me. How do you know this is his issue? He did not show his configuration in a screenshot.
Secondly, the injection of dark frame optimization is fraught with pitfalls- especially for newcomers. Dark frame scaling is not always best or warranted and in practice I believe should not be used to calibrate flat field images. Your screenshot shows master files. In this scenario the Bias is being used to scale a matching dark frame. This is a more advanced idea and can be very confusing.

-adam

Adam Block:
Hi Alonso,
the Master Bias is not being used in light calibration unless the "optimize master dark" has been selected, see picture below to locate it in WBPP. This is because the bias signal is already included in the master dark, therefore the master bias in not necessary when they have the same exposure time.
The optimize master dark option is needed when light and darks have different exposure times, and optional otherwise.

Hope this helps.
Ciao, Mau

Mau,

This post confuses me. How do you know this is his issue? He did not show his configuration in a screenshot.
Secondly, the injection of dark frame optimization is fraught with pitfalls- especially for newcomers. Dark frame scaling is not always best or warranted and in practice I believe should not be used to calibrate flat field images. Your screenshot shows master files. In this scenario the Bias is being used to scale a matching dark frame. This is a more advanced idea and can be very confusing.

-adam

Hi Adam,
thanks for your remark. I just wanted to answer to Alonso's statement "I noticed yesterday while I was WBPP a new set of images, that my BIAS master was not considered as part of the registration/calibration files."
Mau

Adam Block:
Hi Alonso,
the Master Bias is not being used in light calibration unless the "optimize master dark" has been selected, see picture below to locate it in WBPP. This is because the bias signal is already included in the master dark, therefore the master bias in not necessary when they have the same exposure time.
The optimize master dark option is needed when light and darks have different exposure times, and optional otherwise.

Hope this helps.
Ciao, Mau

Mau,

This post confuses me. How do you know this is his issue? He did not show his configuration in a screenshot.
Secondly, the injection of dark frame optimization is fraught with pitfalls- especially for newcomers. Dark frame scaling is not always best or warranted and in practice I believe should not be used to calibrate flat field images. Your screenshot shows master files. In this scenario the Bias is being used to scale a matching dark frame. This is a more advanced idea and can be very confusing.

-adam

Hi Adam,
thanks for your remark. I just wanted to answer to Alonso's statement "I noticed yesterday while I was WBPP a new set of images, that my BIAS master was not considered as part of the registration/calibration files."
Mau

I understand. The likely reason is because he may have been looking at the master files. A masterflat does not need to be calibrated by the bias...whereas it would have been before he ran WBPP and there were raw flats. This is a common little bit of confusion.
-adam

I'll get some snapshots of my configuration later today when I get back from work. I should it started with them since the OP. Sorry about that.

Alonso.

I'm a PixInsight newb and this is just a WAG but I use WBPP a lot and in my experience the WBPP seems to be pretty picky about pairing calibration frames with other calibration frames and lights. If your camera sensor temperature, gain, or offset were any different than the other frames it might reject it as a good match for calibrating the darks. You might be able to tweak settings to make it more lenient but off the top of my head I am not sure how.

Also note that bias frames are used by WBPP to calibrate darks, and dark flats. The latter of which are used to calibrate flats. The bias will not show up in the calibration flow for the lights because they have already done their job.

This might be another reason to use PI to generate your masters. I have no experience with the ASI Air so I can't say if the process is similar.

Again, I am pretty new at this so please take this with a grain of salt and if I'm wrong I hope someone will set me straight.

Good Luck!

Edited:

Wow! in the time I was distracted in the middle of replying the experts have already responded! What a great community!

Ok as promised, here is my WBPP configuration where BIAS are not being taken into consideration.

This is because of the reason I stated earlier. You have a masterflat. A masterflat is composed of a stack of calibrated flats. It does not need to be calibrated (again). Your dark matches your light frame. So..that is it. Everything is good. No use for the bias. BUT remember... if you had the RAW flats as a group in the flats area....then you WOULD see the bias in play.

Please please watch my Definitive Guide to WBPP in this playlist!
https://www.youtube.com/watch?v=VKOTCuqD2Qs&list=PLAzMa9eIVQkBmzPneF8hCgqwkrxsk7CDn
specifically start here!
https://www.youtube.com/watch?v=sZmHbxIxZeM&list=PLAzMa9eIVQkBmzPneF8hCgqwkrxsk7CDn&index=3

-Adam Block

Adam Block:
This is because of the reason I stated earlier. You have a masterflat. A masterflat is composed of a stack of calibrated flats. It does not need to be calibrated (again). Your dark matches your light frame. So..that is it. Everything is good. No use for the bias. BUT remember... if you had the RAW flats as a group in the flats area....then you WOULD see the bias in play.

Please please watch my Definitive Guide to WBPP in this playlist!
https://www.youtube.com/watch?v=VKOTCuqD2Qs&list=PLAzMa9eIVQkBmzPneF8hCgqwkrxsk7CDn
specifically start here!
https://www.youtube.com/watch?v=sZmHbxIxZeM&list=PLAzMa9eIVQkBmzPneF8hCgqwkrxsk7CDn&index=3

-Adam Block

Thank you so much for your reply Adam, I feel relieve to know that everything is working good as you said.

I am definitely watching right now your video series! Amazing work putting that together. Thank you for sharing.

I had the same issue a while back! Seems you have it figured out already, but what I ended up doing is just using asiair’s autorun to take 20 or so darks / biases / flats and just bringing all the files into WBPP and letting it sort them out and create the masters.

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