Author Topic: Comet alignment problem  (Read 2723 times)

Offline si_

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Comet alignment problem
« on: 2014 August 25 07:41:36 »
Hi all - looking for some help aligning comet subs using the comet alignment process.

I have a number of subs that have been calibrated and debayered that I am trying to run through the comet align process but it refuses to load the files and gives this error message "*** DATE-OBS keyword not found or invalid:".

I have searched for any reference to this anywhere and can't come up with anything.

Does anyone know what this means and how I get around it?

Thanks

Offline pfile

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Re: Comet alignment problem
« Reply #1 on: 2014 August 25 12:03:50 »
i think the CometAlignment process depends on the capture time to sort the images in the correct order and try to predict where the comet should be from image to image.

if this keyword is not in your fits files then it explains the problem. not sure how to get capture times into fits files that don't have them in any sort of automatic way. normally your capture software writes this fits keyword…

rob

Offline si_

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Re: Comet alignment problem
« Reply #2 on: 2014 August 25 12:10:39 »
Thanks Rob, I have checked the FITS header and the capture time is correctly recorded so I'm a bit stuck on why this won't work.

Offline Don

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Re: Comet alignment problem
« Reply #3 on: 2014 August 25 15:11:05 »
There was a bug regarding the format of the DATE-OBS value that would cause this error, and it was fixed a while back. 

If your PixInsight version is not up to date, try updating.  The current version is 1.08.02.1098.

Don

Offline pfile

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Re: Comet alignment problem
« Reply #4 on: 2014 August 25 15:13:30 »
don is right, i had forgotten about that bug…

rob

Offline si_

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Re: Comet alignment problem
« Reply #5 on: 2014 August 25 15:26:55 »
unfortunately that is the version I am running, looks like the bug is still there?

Offline si_

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Re: Comet alignment problem
« Reply #6 on: 2014 September 08 13:02:10 »
still struggling with this if anyone can help?

Offline Jason Tackett

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Re: Comet alignment problem
« Reply #7 on: 2014 September 08 13:38:22 »
Would you mind uploading some subframes to Dropbox or somewhere similar? Maybe two raw subframes (uncalibrated) and then two calibrated & debayered subframes. I will check tonight if I get the same message with CometAlignment. Looking at these pairs may help see if the date/time information was dropped somewhere along the calibration process. Could you share some details about how you calibrated your subframes?

Jason

Offline si_

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Re: Comet alignment problem
« Reply #8 on: 2014 September 09 01:26:51 »
Hi Jason

Thanks for the offer - i'll sort out the files this evening and put them in dropbox as you ask.

cheers

Offline Jason Tackett

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Re: Comet alignment problem
« Reply #9 on: 2014 September 10 18:53:27 »
I get the same error when I try to open your uncalibrated .fit file with CometAlignment: "*** DATE-OBS keyword not found or invalid".

The PixInsight file explorer shows that your image has information for TIME and DATE (first image below), but it does not have information for DATE-OBS, which is the camera time stamp.

It looks like DATE-OBS information is required by this process...I'm not sure how to add that information after the fact. Hopefully someone can lend some advice on how to proceed.

For reference, the second image below shows the DATE-OBS field recorded in a .CR2 file from my Canon DSLR.

Jason

Offline si_

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Re: Comet alignment problem
« Reply #10 on: 2014 September 12 17:06:07 »
Thanks Jason. Yes hopefully there is a way to get this to work.