Irregular Mosaic - ...
 
Share:
Notifications
Clear all

Irregular Mosaic - A panel looks "burned"


(@jk_olivo)
Molecular Cloud Customer
Joined: 8 months ago
Posts: 4
Topic starter  

Good morning everyone,

I am quite new to APP and to astrophotography in general. My actual project is a 2x2 mosaic of Andromeda Galaxy. So far, I only got 3 out of 4 parts of the mosaic, but I decided to process them anyway on APP to see how it works.

The result is pretty strange. Even though each panel looks somehow OK before integration, that is what I got after integration (see attached picture). The South-West panel is completely "burned" and the North-West panel has the background much more illuminated 🙄. Also, the North-West panel is too tilted as compared to the other two, but this is probably due to the camera that was slightly rotated during that photo session. 

M31 Mosaic St

Few comments on the parameters I have chosen:

  • 3/ Analyse Stars 
    • I set that to 3000
  • 4/ Register
    • Quadrilaterals, scale start at 5, scale stop at 12, use dynamic distortion correction, same camera and optics. Registration mode mosaic, registration model projective.
  • 5/ Normalize
    • Mode advanced, multiply-scale, BWMV. Background neutralisation enabled
  • 6/ Integration 
    • Integrate all together, automatic integration, composition mode full, 1st degree LNC with 3 iterations. I have enabled the MBB at 10%

For information, disabling the MBB does not help. 

Any idea of the reason of this issue ? Perhaps is it due to the fact that one panel is missing ?

Thanks a lot for the help 😀 

This topic was modified 6 months ago by Jacopo Olivo

ReplyQuote
(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4740
 

No, this is likely because of differences in the panels themselves. In the background etc. the calculation becomes different then. Maybe there is a bit of an issue with that panel, difficult to judge. What happens when you use the LP tool (for light pollution)?


ReplyQuote
(@jk_olivo)
Molecular Cloud Customer
Joined: 8 months ago
Posts: 4
Topic starter  

Hello Vincent,

Thanks for your quick reply. I did not use (yet) the LP tool. I will give a try later. Also, the different panels looks quite OK before processing. I post here some shoots of the different panels (not calibrated)

Schermata 2021 12 03 alle 14.20.36
Schermata 2021 12 03 alle 14.20.53
Schermata 2021 12 03 alle 14.20.16

 


ReplyQuote
(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4740
 

Yes on their own they seem to be fine, but there can be some differences that get more extreme when APP calculates the overall mosaic. This should be able to be corrected with the Light Pollution tool though. If that doesn't work well there might still be a data issue which I can look at.


ReplyQuote
(@jk_olivo)
Molecular Cloud Customer
Joined: 8 months ago
Posts: 4
Topic starter  

@vincent-mod

Hello Vincent,

Unfortunately, in these days I have lost the access to the hardware I was using to run APP. I am now buying a dedicated workstation. 

Nevertheless, following your suggestion I have tried to use the tool for light pollution removal. The result was not good and I did not manage to improve the picture. Then, I have found this post (link) and I have tried to do not use the LNC in the registration phase. It looks much better, even though for some other reasons one of the panel had some issues during the normalization phase, with some green halo appearing on the image. 

I will try again with the new hardware and keep you posted.

Thanks a lot once again,

Jacopo

This post was modified 6 months ago by Jacopo Olivo

ReplyQuote
(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4740
 

Oeh that's not nice. Good luck with the new system!

Good find on that related issue, though I wouldn't expect the overlapping to be such an issue for you.


ReplyQuote
Share: