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Moon Mosaic - problems with brightness differences

PostPosted: Mon Nov 25, 2019 11:03 pm
by AstroChris
Hey folks!

Last week I took a mosaic of the moon using a 3x Barlow, a ZWO ASI120mm mini mono on my 150/750mm Newtonian.
It was bitterly cold and when i finished the session and lost two fingers to the coldness I went inside.
Next days then processing: Autostakkert and Registax. I didn't touch the settings from image to image to keep the image even and same. So the thinking.

It turned out that (even though I like the result very much) some parts of the image have brightness differences. That might be due to thin clouds or seeing our stuff. So adjusting the brightness from sub-image to sub-image is just a pain in the ***. Every time i am happy with two neighbors and then keep that brightness, three sub-images left there is a difference again. If I then align that brightness, there is a difference to the images adjusted beforehand.... And so on and so on.

The image:

Image

Link to bigger version:
https://catchingphotons.de/wp-content/uploads/2019/11/2019-11-10-Moon_Mosaik_extrasharp_and_bright_WEB.jpeg

Q: is there a short cut? Some trick? Anything like a brightness normalisation in Autostakkert or stuff? That would be great.
I one did a mosaic without Barlow lens and it turned out just great! The overall time of that acquisition was much shorter back then. This time it took a while so seeing/clouds had their chance.


Any suggestions are welcome :-)
Thanks and greetings
Chris

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Re: Moon Mosaic - problems with brightness differences

PostPosted: Tue Nov 26, 2019 7:41 pm
by Bizibilder
A lovely image. Hopefully these notes will help you:

You can also see a few of the joins (across the disc 2/3 of the way up).

Try:
Stack each pane in autostakkert.
Use IMPPG to apply Lucy-Richardson deconvolution (rather than wavelets) https://greatattractor.github.io/imppg/
Then crop the edges off all the panes - make sure you get all the white edges and any black mis-alignments. Don't play with the image brightness settings.
Try stitching together using Microsoft ICE (Image composite editor) (this should "auto-adjust" the brightness between panes).
Then maybe adjust the overall brightness/contrast.

See how you get on ;)

Just a note: always work in TIFF format until the final step when you can convert to PNG or JPEG

Re: Moon Mosaic - problems with brightness differences

PostPosted: Wed Nov 27, 2019 6:44 pm
by AstroChris
Thanks for the advice!
I triedto stitch manually using GIMP and "difference" layer. When it's black on overlapping sections, or should fit ok. But doing it manually is a lot of work and doesn't always fit perfectly.

I will try Microsoft ICE and report fort that.

Greetings
Chris

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Re: Moon Mosaic - problems with brightness differences

PostPosted: Mon Jan 27, 2020 6:59 am
by AstroChris
It worked like perfectly!!

Thanks for the trick!

Image: moon
Scope: Skywatcher 750/150 pds explorer
Cam: ZWO ASI 120 MC-S Colour
3x Barlow
1000 frames - stacked 10%best Autostakkert2
~6 images/row


Image


Greetings
Chris


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Re: Moon Mosaic - problems with brightness differences

PostPosted: Mon Jan 27, 2020 12:02 pm
by carastro
Nice image.

Yes some-one introduced me to ICE recently while I was doing my flaming star and tadpoles mosaic, is certainly does work very well and is very easy.

Carole

Re: Moon Mosaic - problems with brightness differences

PostPosted: Mon Jan 27, 2020 6:50 pm
by Bizibilder
Excellent Chris!! You have the exposure bang on too (easiest check is can you see the detail inside Aristarchus?). Looks really good blown up to full size.

Re: Moon Mosaic - problems with brightness differences

PostPosted: Sun Feb 02, 2020 8:04 am
by AstroChris
Hey folks!!

This is a short clip of my result...
A journey to the beautiful moon!
Thanks for the help down the road!

https://youtu.be/-kNti90gUus

Hope you like it ( i do ;) )
Greetings
Chris

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