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2022-09-02: APP 2.0.0-beta4 has been released !

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Mosaic problem


(@fentonm)
Molecular Cloud Customer
Joined: 2 years ago
Posts: 7
Topic starter  
Screenshot 2022 08 04

Here's my first-ever mosaic, a 2 x 2 of NCG7000. got my coordinates from Telescopius, imported them, and created a Plan in my ASIAir. Set the overlap (in Telescopius) to 15% and processed the images (15 300-second exposures per panel) using Astro Pixel Processor. Any idea what went wrong? What would you all need to know to help me fix the problem? I selected "mosaic" under the register tab and scale stop of 10. In the integrate tab, I used LNC with 1st degree option and default iterations (3). I also enables multiband blending (10%). Yikes!


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4987
 

Mmm, did you also switch on distortion correction and advanced normalization, star amount to about 2000? If so, I suspect you're missing some overlap in the middle where there might simply not be data. Can you tell maybe by looking at the panels separately, if they have a bit of overlap?


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(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1881
 

@fentonm Looks like you're using an ASI533 camera with a square sensor. I am afraid you simply didn't plan the mosaic correctly. Would you by chance have screenshots of images of the individual panes?


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(@fentonm)
Molecular Cloud Customer
Joined: 2 years ago
Posts: 7
Topic starter  

@wvreeven - here's the panels I used from Telescopius coordinates and what the actually images were using Astronomy.net.


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(@fentonm)
Molecular Cloud Customer
Joined: 2 years ago
Posts: 7
Topic starter  

@wvreeven - and yes, I'm using an ASI533MC pro. Here's the panels I wanted to use per Telescopius... I imported the CSV data into the ASIAir.

Telescopius panels

 


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(@fentonm)
Molecular Cloud Customer
Joined: 2 years ago
Posts: 7
Topic starter  

@vincent-mod - dynamic distortion correction, yes, but not advanced normalization.


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(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1881
 

@fentonm It looks like Telescopius or ASIAir didn't get something right. The whole in the middle isn't caused by APP. There are no data there.


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(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1881
 

@fentonm I have had another look at your mosaic plan and at your images. The camera was rotated at about 40° which introduced the gap in the center. Please make sure that the camera is rotated with the sensor sides straight up. You can do this by looking at the USB ports on the back of the camera. Those are (more or less) aligned with the sensor and will help you find the right rotation. If your telescope doesn't allow for rotating the camera then you can tell Telescopius the rotation angle for your camera and it will take it into account when creating your mosaics. Either of the two will prevent gaps in the future. 

For now you can shoot images centered on the gap so your mosaic still is usable. 


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(@fentonm)
Molecular Cloud Customer
Joined: 2 years ago
Posts: 7
Topic starter  

@wvreeven - THanks!!!


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(@wvreeven)
Galaxy Admin
Joined: 4 years ago
Posts: 1881
 

@fentonm Does that mean that that indeed was the problem and you managed to solve it?


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(@fentonm)
Molecular Cloud Customer
Joined: 2 years ago
Posts: 7
Topic starter  

@wvreeven - I did measure the rotation angle in advance this time and tried again using that rotation value when getting my location data from Telescopius. The 4 panels weren't perfectly aligned in the end, but I didn't have to crop too much. My concern now is that there are areas in the mosaic that looked stretched,with egg-shaped stars, but other areas look fine (see attached photo). I integrated and looked at each of the 4 panels separately and they all look perfect (no stretching). Thoughts as to what's going on? Thanks!

NANeb rot crop lpc cbg St DN

 


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(@vincent-mod)
Quasar Admin
Joined: 5 years ago
Posts: 4987
 

You can try again, but without turning on dynamic distortion correction. Sometimes, when it's not needed, it can cause artefacts.


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(@fentonm)
Molecular Cloud Customer
Joined: 2 years ago
Posts: 7
Topic starter  

@vincent-mod - that fixed the problem! Thanks so much!

NANeb NS crop lpc cbg St DN 1 (2)

 


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