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Comet registration when using two different image sets

3 Posts
2 Users
Main Sequence Star
Joined: 2 years ago
Posts: 14
Topic starter  

I am running into a problem performing 1-star comet registration on two different image sets from the same night.

I use a barn door tracker. It can track for about 30 - 45 minutes. After that I have to reset/rewind, resume tracking, and recenter the camera on the comet field.  The delay is only a few minutes of time, but the second image set is offset (and slightly rotated) compared to the first image set.

If I try to register all images in APP, the resulting integration stack will have a double comet nucleus, and the double star trails show that there is also a slight angular misalignment. Somehow the software does not appear to be properly keeping track of the registration changes in the second set of images.

As a workaround I am performing normal (multi-star) registration on all images, saving those registered (and normalized) images, then registering again using comet/1-star mode, then performing final integration.

Am I using an incorrect workflow? Am I asking APP to try to do too much at once?

(First attached image shows final integration result after using the workflow method I described above. You can see the shift/rotation difference between the two image sets. Second image is a final integration of about 175 frames of comet 104P Kowal from last night.)

Thank you in advance,
Tom Krajci

New Mexico

Screenshot 2022 03 07 100829
2022 03 06 104P Kowal

Main Sequence Star
Joined: 2 years ago
Posts: 14
Topic starter  

I did a quick double check of my comet image workflow on a small sample of images.

Screenshot 2022 03 10 135100

 This shows the integrated result after using comet/1-star registration on three different image sets from the same evening. You can see there are differences in positioning and rotation of the camera frame.

But a close look at the final stack/integration shows:

Screenshot 2022 03 10 135156

...the comet images are not accurately registered, so the nucleus is triple.  Also, the stars do not show motion in a straight line between the three image sets, so there is also a problem with keeping track of the necessary rotation for proper registration.

At the present moment my workflow is to calibrate and register all frames using normal these registered (and normalized) frames...clear/reset/restart APP and then register all these frames using comet/1-star registration.

Universe Admin
Joined: 6 years ago
Posts: 5701

I think we can do the same question with the data I already asked for you to upload. 🙂

Tom Krajci reacted