Sharp Cap will not live stack

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AJS1
Posts: 4
Joined: Fri Aug 18, 2017 7:15 pm

Sharp Cap will not live stack

#1

Post by AJS1 »

I am new to this forum and Sharp Cap so I apologize in advance if this question has been asked and answered before. When I try to use live staking I get the following error message:

"Frame not stacked because less than three stars found in frame image"

There are lots of stars in these images (sometimes 100's). I am using ZWO ASI071 Camera and an 8" edge HD telescope (in case this matters). I have searched other forums like CN and found no answer. The question has been asked (a few years back) but no answer was given that helped me with the current version of SC. I have not changed any of the default settings on the Live Stack Tab. Any help would be much appreciated.
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admin
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Re: Sharp Cap will not live stack

#2

Post by admin »

Hi,

you need to check and adjust the star detection settings in the 'Alignment' tab as SharpCap is not managing to find the stars.

Good starting points are :

Noise Reduction 0.5 or 1
Minimum Star Width 0 or 1
Maximum Star Width 16+
Black Level Threshold 20
Digital Gain Off

Tick the 'Highlight detected stars' box so that you can see which stars are being picked up and watch the counts underneath to see how the number of stars detected responds to your changes. When you have a combination that works your stacking should then proceed.

Robin
AJS1
Posts: 4
Joined: Fri Aug 18, 2017 7:15 pm

Re: Sharp Cap will not live stack

#3

Post by AJS1 »

Thanks, I made these changes but when I reduce the noise reduction to less than 2, I get a hot pixel warning. Should this be ignored?
AJS
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Re: Sharp Cap will not live stack

#4

Post by admin »

Hi,

not quite ignored completely, but you can certainly use settings that show this warning.

It's telling you that hot pixels *could* be a problem with those settings if you have a lot of them. In most cases even if there are hot pixels then the real stars will get used for alignment as they are bigger/brighter. However if you had a very dim image and a camera that was creating a lot of hot pixels then you could end up with the alignment using the hot pixels as stars which isn't good! Perhaps I need to make the warning a little more subtle if it scared you off using those settings.

cheers,

Robin
AJS1
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Re: Sharp Cap will not live stack

#5

Post by AJS1 »

Thanks Robin
I guess that the red letter warning did concern me. It takes a little more to scare me... like almost dropping my OTA. :D
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Re: Sharp Cap will not live stack

#6

Post by admin »

Hehe, I did that once. Fortunately it was a refractor (and a relatively cheap one too) and it survived except for a split dewshield. It's still held on with tape to this day :)

cheers,

Robin
robrj
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Joined: Fri Feb 17, 2017 1:03 am

Re: Sharp Cap will not live stack

#7

Post by robrj »

admin wrote: Tue May 01, 2018 4:29 pm Perhaps I need to make the warning a little more subtle if it scared you off using those settings.
I don't think I'd change it. I like that it stands out. If my images are stacking smoothly, it wouldn't concern me but if they aren't it's nice to see a red flag as to a possible cause.
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