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WinJupos smears moons

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#1 1stSolo

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Posted 17 September 2021 - 09:37 AM

Does WinJupos only use ephemerides to determine orientation of the planet? It seems to improve the surface but the moons and their shadows are smeared into long lines after derotation.
Or am I doing something wrong? I’ve 4 RGB videos stacked individually and sharpened, then measured and derotated in WinJupos.

#2 bunyon

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Posted 17 September 2021 - 09:49 AM

Yes, it will smear the moon. Most folks process moons and planet separately.


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#3 1stSolo

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Posted 17 September 2021 - 09:56 AM

By processing separately do you mean in WinJupos or in Photoshop/GIMP?
If moon shadows are smears it will be hard to get them off the derotated image…

#4 bunyon

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Posted 17 September 2021 - 10:17 AM

Ah. You are working with shadows and transits. Maybe someone else will have some advice but I think that doesn't work. (That is, yes, the shadow will be smeared. 

 

Process separately meant in the final. One process to get the planet, one to get the moon, then composite them. The moons generally need different sharpening anyway.


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#5 dcaponeii

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Posted 17 September 2021 - 10:46 AM

Ah. You are working with shadows and transits. Maybe someone else will have some advice but I think that doesn't work. (That is, yes, the shadow will be smeared. 

 

Process separately meant in the final. One process to get the planet, one to get the moon, then composite them. The moons generally need different sharpening anyway.

What I do is to cut out a section of the shadow on a single frame of the planet near the UTC of the derotation.  Then paste it onto the derotated planet as a layer over the top of the smeared out moon shadow.  Same with the moons themselves as they will smear (or get duplicated) by the derotation as well.  You can use your clone tool to remove the duplicate moons from your image.


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#6 Kokatha man

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Posted 17 September 2021 - 09:11 PM

Short answer is that unless you get into involved photo-shopping procedures akin to what Don is describing above you are in trouble with Galilean Moons & their shadows transiting Jupiter when using WinJUPOS.

 

If the moon has an orbital speed matching Jove's rotational speed you can get away with it at times. (which off-hand I think is Io - but I'm old and I forget things I did yesterday, even though I image regularly rofl2.gif )


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#7 daniele.bonfiglio

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Posted 01 October 2021 - 03:26 AM

Indeed, this is what I get when derotating with WinJupos three stacks taken within a total time span of 9 minutes, with Europa and its shadow and Ganimede. The moons in particular do smear out. At the beninning I was naively expecting that the moons would be derotated as well (I mean, they would move) and I spent a lot of time tring to modify the alignment of my three image measurements to get the moons match in the derotated image. Finally I made a simple test: I derotated with a reference time one hour either later of before my measurements, and the position of the moons in the derotated image did not change.

 

2021-09-23-1950_6_crop.jpg


Edited by daniele.bonfiglio, 01 October 2021 - 03:50 AM.


#8 Ittaku

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Posted 01 October 2021 - 05:36 AM

Yes, just stack them separately with a regular stack and mask them into the blurred image. Don't derotate moon or shadow transits at all though (Ganymede you can almost get away with it since it transits only marginally slower than the rotation of Jupiter.)




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