Is there a guide to the most recent Weighted Batch Preprocessing script in Pixinsight.

[Ouroboros]

Anyone know of a recent guide to using the most recent WBPP v2.5.0?

For years I’ve always pre-processed manually in PI. I had a poor result years ago using BPP so gave it up as a bad job. At least manually I can keep track at each stage. Go back or repeat a stage if I’m not happy etc. But it is a bit of a long haul frankly.

Now, I’m aware of the definitive WBPP videos by Adam Block and others. So I’ve been viewing some of those. Then I updated Pixinsight and realised the latest version v2.5.0 looks somewhat different again. Oh no! 😃

So, what to do? Is there a recent guide or do I just slog through the old guides and work out what’s changed? 

[wimvb]

Adam Block has updated some of his videos to reflect changes in the workflow. AfaIk, those are the most up to date videos out there.

Edited September 9, 2022 by wimvb

[scotty38]

The Adam Block videos should get you up and running with WBPP no problem and until you're comfortable I think you can probably safely "ignore" (I tried to choose that word carefully 🙂 ) the latest changes but if you go to the PI forum there is a breakdown of the new additions.

[Ouroboros]

OK @wimvb and @scotty38.  Thanks. I guess I’ll have to do the leg work with earlier videos.

A couple of things I’m not sure on ….

Would I right in thinking I can just drop a previously prepared master dark into the Dark files section of WBPP?

Also …. I don’t take dark bias frames now at all because apparently one shouldn’t with the ASI2600.  So I don’t use bias files at all. 

I do, however, take dark flats of the same duration as the flat frames. 

Am I right in thinking the flat darks can be loaded as Darks and WBPP will know to only subtract those from the flats? It won’t try and subtract the dark flats from the Lights will it? 

[Budgie1]

4 hours ago, Ouroboros said:

Would I right in thinking I can just drop a previously prepared master dark into the Dark files section of WBPP?

Yes, you can just use a previous Master Dark of the same exposure and sensor temp as the lights.

4 hours ago, Ouroboros said:

Also …. I don’t take dark bias frames now at all because apparently one shouldn’t with the ASI2600.  So I don’t use bias files at all. 

I do, however, take dark flats of the same duration as the flat frames. 

Am I right in thinking the flat darks can be loaded as Darks and WBPP will know to only subtract those from the flats? It won’t try and subtract the dark flats from the Lights will it? 

Leave the Bias frames blank and add the Dark-Flats to the Darks menu and WBPP with separate them from Darks using the exposure time.

You should also see a tick in the "Darks" box on the Flats on the Calibration tab.

[wimvb]

4 hours ago, Ouroboros said:

Would I right in thinking I can just drop a previously prepared master dark into the Dark files section of WBPP?

Correct

4 hours ago, Ouroboros said:

Also …. I don’t take dark bias frames now at all because apparently one shouldn’t with the ASI2600.  So I don’t use bias files at all. 

I do, however, take dark flats of the same duration as the flat frames. 

Also correct. Darks, flats and lights all contain the bias information. If you subtract a dark from a light frame, you also subtract the bias. Bias frames were used with ccd images, because they allowed one to use the same master dark for different exposure times. But with cmos, you need to match your darks to your light frames (exposure tine, temperature, gain and offset).

Flat darks need to match flat frames and are used to calibrate those.

4 hours ago, Ouroboros said:

Am I right in thinking the flat darks can be loaded as Darks and WBPP will know to only subtract those from the flats? It won’t try and subtract the dark flats from the Lights will it? 

You will probably need to set the exposure tolerance lower, but wbpp will try to match darks with flats and lights

[scotty38]

23 minutes ago, wimvb said:

You will probably need to set the exposure tolerance lower, but wbpp will try to match darks with flats and lights

You shouldn't need to change this for darks matching etc but if for any reason the correct files are not linked automatically you can turn that off and match them manually.

[wimvb]

1 hour ago, scotty38 said:

You shouldn't need to change this for darks matching etc but if for any reason the correct files are not linked automatically you can turn that off and match them manually.

In my case, I have flats for each filter (lrgb) with similar but not identical exposure times, and if I don't set the exposure tolerance to 0, wbpp won't match flats and darks correctly.

[scotty38]

7 hours ago, wimvb said:

In my case, I have flats for each filter (lrgb) with similar but not identical exposure times, and if I don't set the exposure tolerance to 0, wbpp won't match flats and darks correctly.

ok same here too. I create master flats plus I have the filter names when I create masters in the first place but I'll fire it up later and check how mine get matched as I never have to do it with cal files

[Ouroboros]

10 hours ago, Budgie1 said:

Yes, you can just use a previous Master Dark of the same exposure and sensor temp as the lights.

Leave the Bias frames blank and add the Dark-Flats to the Darks menu and WBPP with separate them from Darks using the exposure time.

You should also see a tick in the "Darks" box on the Flats on the Calibration tab.

OK. Thanks. Does a master file store the duration of the original frames in its header file then? It must do presumably for WBPP to know what to do with it. 

[scotty38]

20 minutes ago, Ouroboros said:

OK. Thanks. Does a master file store the duration of the original frames in its header file then? It must do presumably for WBPP to know what to do with it. 

There are a boatload of ways to identify files for WBPP, fits header being one of them. Let me dig out a link as there's a nice write up of how some of this is done.

[scotty38]

Here you go:

https://pixinsight.com/forum/index.php?threads/how-wbpp-2-4-5-retrieves-the-information-of-files-in-the-session.18806/

[Ouroboros]

WoW! @scotty38.  Thanks. So much info.  

[Ouroboros]

I've been going through Adam Block's definitive guide to WBPP videos.  He's very thorough.  As someone  said earlier, those videos are pretty much up to date.  It looks like I've chosen a good time to revisit WBPP.  Some of his videos are only a few days or weeks old. 

I'm quite impressed how powerful WBPP has become.  I can see why people say WBPP is the recommended or preferred way to preprocess. But it needs careful setting up and a thorough understanding of what it's doing.  This is going to be a longish learning curve for me.  I'd like to get to the point where I have a typed workflow sheet to follow.  I use a typed workflow sheet to preprocess manually.  It's three pages of typed A4 - and is basically a summary of the preprocess described by Warren Keller in Part 1 of his Inside Pixinsight 2nd Ed. 

 

[Ouroboros]

Incidentally, when do people look at Subframe Selector when using WBPP? Or maybe they don't use it.

In my manual workflow  I tend to start out by using the Blink process to weed out the really bad lights. Then I use Subframe Selector after debayering.  I use SS to identify any frames with eggy stars or low numbers of stars etc.  But I like to use it to help weed out dodgy lights visually rather than just rely on weights.    I don't quite trust weights somehow. 

Edited September 10, 2022 by Ouroboros

[scotty38]

2 hours ago, Ouroboros said:

Incidentally, when do people look at Subframe Selector when using WBPP? Or maybe they don't use it.

In my manual workflow  I tend to start out by using the Blink process to weed out the really bad lights. Then I use Subframe Selector after debayering.  I use SS to identify any frames with eggy stars or low numbers of stars etc.  But I like to use it to help weed out dodgy lights visually rather than just rely on weights.    I don't quite trust weights somehow. 

That's another step forward that WBPP has taken with the accuracy of weighting and I believe the need for subframe selection is not as great as it was. I still like to use blink though but again maybe not necessary. There has been discussion on this recently too, I'll see if I can find that too.....

[Ouroboros]

Thanks, Scotty.  With a 7 year old MacBook it’s good to throw out as many duff frames as I can before I start in order to save time on the processing. 

[StuartT]

If I'm honest, I am struggling with 2.5.1 - it seems to have a lot of new stuff which is causing problems for me. 

Presumably there must be a way I can revert to the previous version of WBPP? It's all kept in C:\Program Files\PixInsight\src\scripts\WeightedBatchPreprocessing so if I can find a download of the files that made up the previous version somewhere, I could just replace all the files right?

[Ouroboros]

4 hours ago, StuartT said:

If I'm honest, I am struggling with 2.5.1 - it seems to have a lot of new stuff which is causing problems for me. 

Presumably there must be a way I can revert to the previous version of WBPP? It's all kept in C:\Program Files\PixInsight\src\scripts\WeightedBatchPreprocessing so if I can find a download of the files that made up the previous version somewhere, I could just replace all the files right?

Dunno, Stuart. There was a very recent update/bug fix to WBPP 2.5.1 script.  Might be worth checking that out first? 

[Ouroboros]

I’ve been watching Adam Block’s videos and then discovered this recently published YouTube video.  To my as yet inexperienced eye it seems quite a good summary of how to use the script. 

 

[StuartT]

18 minutes ago, Ouroboros said:

I’ve been watching Adam Block’s videos and then discovered this recently published YouTube video.  To my as yet inexperienced eye it seems quite a good summary of how to use the script. 

Great! Thanks. I have been looking for a video on 2.5.1 but didn't see one. 

EDIT: ok so this is a nice overview of WBPP, but it doesn't tell you about the many new features.

Edited September 13, 2022 by StuartT

[Ouroboros]

As a first time newbie to WBPP I’m not sure what the new features are.  

Just now I’m getting error messages saying the Light frame’s exposure differs from the Master Dark exposure.  This is because  neither my master dark file (nor master flat file)  contain the exposure duration. Is there a way to simply tell WBPP what the duration is?  

 

 

 

[StuartT]

14 hours ago, Ouroboros said:

As a first time newbie to WBPP I’m not sure what the new features are.  

Just now I’m getting error messages saying the Light frame’s exposure differs from the Master Dark exposure.  This is because  neither my master dark file (nor master flat file)  contain the exposure duration. Is there a way to simply tell WBPP what the duration is?  

Normally WBPP will read the exposure time from the FITS header. But if it can't for some reason, you can just remove your darks, then re-add them using the "Custom" button. This will allow you to specify things like filter name, exposure time, binning etc

The other way to do it would be to go up to the "calibration settings" (top of the calibration tab) and select the darks from there (usually it's set to Auto, but the drop down should allow you to pick a different file)

Edited September 14, 2022 by StuartT

[Ouroboros]

Thanks for that, @StuartT.  Somehow I overcame the problem, but I’m not sure how. I reloaded the two master darks which I’d renamed to include the duration. Don’t think I did anything else. Nevertheless it knew the durations afterwards. 

[StuartT]

33 minutes ago, Ouroboros said:

Thanks for that, @StuartT.  Somehow I overcame the problem, but I’m not sure how. I reloaded the two master darks which I’d renamed to include the duration. Don’t think I did anything else. Nevertheless it knew the durations afterwards. 

Apologies, I should have said that WBPP can read key info from both the FITS header and the filename.

Glad you got it sorted out. WBPP is really superb once you get used to it.