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Two Questions Regarding Pre-Processing in Pixinsight

Pleiades Astrophoto PixInsight Processing Bias Frames Calibration Deep Sky
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Jerry Gerber avatar
Jerry Gerber avatar
I made two problems for myself:

1.  I didn't make my bias frames the same temperature as my lights, the lights are at -10c and the bias frames are at 0c.  Darks are same temperature as lights.  Is there anything I can do to compensate for this other than re-shoot the bias frames?    I use the bias frames to calibrate flats, but only use darks and flats to calibrate lights. 

2.  A few days ago I changed the filter name in the filename from "UV-IR" to "UV-IR Cut" and some of the frames have one or the other.  Pixinsight's WBPP thinks they are different filters and will output them as 2 masters (OSC) rather than just one.   What's the best way to combine these 2 unstretched, integrated calibrated masters?   The PI Light Integration process requires 3, not 2 images, so I guess I could merely duplicate one, but is there a better way to combine these 2 masters?

Thanks,
Jerry
David Rosenthal avatar
David Rosenthal avatar
1.  Temperature of bias frames will not make any difference. The exposure time is too short for thermal noise to contribute. 

2.  Go into the images that have the old filter name and edit the FITS header values to match the new name
Helpful Concise
Jerry Gerber avatar
Jerry Gerber avatar
Thanks David.  Changing the FITS header manually for 160 fie names is too laborious.  I think there's a better way..
andrea tasselli avatar
andrea tasselli avatar
2. Average them together with PixelMath, don't need to do anything else.
Jim Raskett avatar
Jim Raskett avatar
https://youtu.be/fuyI0_FHQmI?si=QuEw8j_LY6KlshnE

Adam Bloch video on how to edit a batch of fits file headers.
Jerry Gerber avatar
Jerry Gerber avatar
There are two batch scripts for PI that can edit multiple FIT headers at once to modify any part of the header but neither of them work. 

The first one is:=elementor-heading-title elementor-size-defaultBatchFITSKeywordEdit  (https://cosmicphotons.com/scripts/)I get an error message when I try to install it. 

The other one also won't open, ti's called BatchEditFITSSingleKeyword
Jerry Gerber avatar
Jerry Gerber avatar
andrea tasselli:
2. Average them together with PixelMath, don't need to do anything else.

 
andrea tasselli:
2. Average them together with PixelMath, don't need to do anything else.

When you say average them together do you mean "Image01+Image02"?

I tried that with 2 different images and it doesn't seem to add them together..
andrea tasselli avatar
andrea tasselli avatar
Jerry Gerber:
When you say average them together do you mean "Image01+Image02"?

I tried that with 2 different images and it doesn't seem to add them together..


Average means (Image01+Image02)*0.5. There is also a  weighted average procedure which is: (Image01*TotalTimeImage01/TotalTime+Image01*TotalTimeImage02/TotalTime)
Doug Crowe avatar
Doug Crowe avatar
You can rerun them through wbpp using the "add custom" tab to add one of the set of lights and change the filter name. I have had to do this multiple times. It will then combine them into one masterlight.
Jerry Gerber avatar
Jerry Gerber avatar
Doug Crowe:
You can rerun them through wbpp using the "add custom" tab to add one of the set of lights and change the filter name. I have had to do this multiple times. It will then combine them into one masterlight.

That sounds like the simplest approach, I'll try that.
Well Written
Jerry Gerber avatar
Jerry Gerber avatar
Doug Crowe:
You can rerun them through wbpp using the "add custom" tab to add one of the set of lights and change the filter name. I have had to do this multiple times. It will then combine them into one masterlight.

Hi Doug,

I'm not sure how to proceed with the "add custom" dialogue box. \

Do I put the original filter name I want to change (UV-IR)?  Or do I put the new filter name I want to change it to (UV-IR Cut?)
Well Written
Jim Raskett avatar
Jim Raskett avatar
For me, I prefer to use “Custom” routinely. 
It takes a minute longer, but eliminates little differences in datasets.

For “Add Custom “, I believe that you can call the filter anything you like (custom). It won’t matter as long as you do it for all lights.
Doug Crowe avatar
Doug Crowe avatar
As Jim stated you can name your filter anything you want. I have had a few times where one set says filter "1" and the other set says "no filter". I just add the "no filter" set under custom and name the filter "1".
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Yellowfin avatar
Yellowfin avatar
If your image files are on a Windows machine, you can use "Power Rename" to change 160 files at once it will take you about a minute after downloading the tool. I use this all the time when I shoot on different nights with different plan names. It allows me to rename files and works great every time.
Helpful Concise
Jerry Gerber avatar
Jerry Gerber avatar
If your image files are on a Windows machine, you can use "Power Rename" to change 160 files at once it will take you about a minute after downloading the tool. I use this all the time when I shoot on different nights with different plan names. It allows me to rename files and works great every time.

Is "Power Rename" an app or utility?
Doug Crowe avatar
Doug Crowe avatar
Will wbpp combine subs of different filter names if you just change the file name? Doesn't wbpp get the filter name or number from the fits header?
Bill Becher avatar
Bill Becher avatar
I have found that PixInsight likes the filter names to all have the same number of characters. Otherwise you get an error message.
so H, O, R, G, B etc. Not Ha, R, G, B….
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Jerry Gerber avatar
Jerry Gerber avatar
Bill Becher:
I have found that PixInsight likes the filter names to all have the same number of characters. Otherwise you get an error message.
so H, O, R, G, B etc. Not Ha, R, G, B....

deleted.
Jerry Gerber avatar
Jerry Gerber avatar
Bill Becher:
I have found that PixInsight likes the filter names to all have the same number of characters. Otherwise you get an error message.
so H, O, R, G, B etc. Not Ha, R, G, B....

Are you sure about that?   I've been using filter names that don't have the exact same number of characters, such as UV-IR and Ha-Oiii and Sii-Oiii and have not had a problem.  Maybe something else is going on?
Yellowfin avatar
Yellowfin avatar
Hmmm, good point about the filter name being pulled from the FITS header, honestly, I am not sure. I will say Power Rename is a great tool for changing bulk file names if that is ever needed. I would test the Filter renaming and see what happens, worst case you are back to bulk changing the FITS header.