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Question on stacking result - I have a double mars effect? (Pleades/Mars Conjunction)  

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(@dwephoto)
Hydrogen Atom Customer
Joined: 12 months ago
Posts: 2
March 6, 2021 21:44  

I'm a little new to APP - was out shooting Pleades and Mars conjunction - all images from one night, but 2 sessions as took 30 min break...this is the second stacking attempt (with some tweaks in settings), and same as my first - why am I getting a "double mars" effect, yet stars are aligned...I realize planets moving different speed, but this is only about 3 hrs total...I did not think there would be that much motion over that period...I think it is something in my technique!

I did no processing to this.  Enabled MBB 7%.  No dither.  I labeled all the lights as 2 different sessions on import, and stacked all together.  Jpeg attached.

 

Thanks for any advice/pearls of wisdom

David Easton, Winnipeg Canada

pleadies orig 1

 


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(@wvreeven)
Galaxy Admin
Joined: 3 years ago
Posts: 731
March 6, 2021 22:30  

@dwephoto Currently Mars moves about 2100 arcsec a day which means 2100 / 8 = 265 arcses or almost 4.5 arc minutes in 3 hours. That motion may very well become visible in your subs. do you see a displacement in the position of Mars when you compare the first and last subs?


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(@dwephoto)
Hydrogen Atom Customer
Joined: 12 months ago
Posts: 2
March 6, 2021 23:45  

Well Wouter - perhaps you deserve the "Galaxy" designation!  Astronomy is cool!  Nice little pearl of wisdom there i didn't think would factor in...I think you are correct and looking back at things now, it does seem like only logical answer...APP is to smart to screw that up, right!  🙂

Seriously, it was honestly 3-4 hrs and i did try and compare in lightroom, which was another obvious good idea...i screen shot an extreme zoom, and it is still rotated a bit, but i does, to my eye appear to move substantially in the frame.  I have only tried shooting a conjunction with Venus in past, and details fuzzy, but didn't run into this problem.  Regardless, i will maybe stack half of my pics or try some magic in photo shop!  Thanks for the help.

de

Screen Shot 2021 03 06 at 4.36.14 PM

 


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(@svancott)
Hydrogen Atom Customer
Joined: 5 months ago
Posts: 2
March 8, 2021 18:02  
Posted by: @dwephoto

Well Wouter - perhaps you deserve the "Galaxy" designation!  Astronomy is cool!  Nice little pearl of wisdom there i didn't think would factor in...I think you are correct and looking back at things now, it does seem like only logical answer...APP is to smart to screw that up, right!  🙂

Seriously, it was honestly 3-4 hrs and i did try and compare in lightroom, which was another obvious good idea...i screen shot an extreme zoom, and it is still rotated a bit, but i does, to my eye appear to move substantially in the frame.  I have only tried shooting a conjunction with Venus in past, and details fuzzy, but didn't run into this problem.  Regardless, i will maybe stack half of my pics or try some magic in photo shop!  Thanks for the help.

de

Screen Shot 2021 03 06 at 4.36.14 PM

 

This is the exact same issue I had as well, though I had seen some images already discussing the problem so I knew the potential. I shot 160x60s for a little over 2.5 hours. I stacked the best 90% so about 144 which I realized after I did it was not very smart since it would likely pick consequentially and probably exacerbate the mars stretch (or at least not help). 

The solutions I have seen so far are both what you have suggested, shorter integration or photoshop in a single (or reduced stack) of Mars. 

I'm probably not smart enough for the photoshop piece, so will try the shorter stack idea. 


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