SC not stacking images if more than 10 seconds.

Discussions of Electronically Assisted Astronomy using the Live Stacking feature.
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FXModels
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SC not stacking images if more than 10 seconds.

#1

Post by FXModels »

Using 183 Mc pro on a Meade 10” scope. I am trying to stack a perfectly focused trifid nebula. In the last two weeks or so I noticed that sharpcap won’t stack unless the images are around 10 seconds. Same problem for omega nebula and eagle nebula. In fact any area where there are a lot of stars it won’t stack.

Any idea why?
Thank you!
Marc
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Re: SC not stacking images if more than 10 seconds.

#2

Post by admin »

Hi Marc,

can you just confirm if it's images longer than 10 seconds that are having problems stacking or images shorter than 10s? Reading your title seems to imply longer, but the body text of the post seems to imply shorter.

In either case, the first place to check when things won't stack is the alignment settings in the live stacking area, particularly look at the star detection settings - how many stars are being detected (ideally 30 to 100 or so). You can also toggle on the option to show which stars are being detected to see if the detected ones look right or odd.

You can also look in the live stacking log tab, where it should give you some info about why it cannot stack a particular frame.

cheers,

Robin
FXModels
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Re: SC not stacking images if more than 10 seconds.

#3

Post by FXModels »

ahh sorry Robin...

UNLESS I take exposures of LESS than 10 seconds SharpCap will not stack.. Further in the FWHM filter you only see question marks. Also, I am using the default stack routine. There is a caveat to this and this has to do with how congested the field is with stars. See below.

Firstly, when power comes up at 9PM tonight Robin I will check alignment settings and star detection settings. I will turn on the show detected stars setting which I believe is in there.

Ok so here is what I am seeing: I am finding that I can stack as long as I want with objects like the Eagle Nebula or the Lagoon nebula where there are fewer stars. But if I try to stack on the Scutum starcloud and M11, or the Trifid, I cannot stack. It seems that the sheer number of stars is causing an issue.

Does any of this help you? Thanks man.. Love this program brother.
Marc
FXModels
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Re: SC not stacking images if more than 10 seconds.

#4

Post by FXModels »

Robin,
I figured something out that may be of interest.. I had to turn OFF "optimize for faint stars" to get it to stack again. Now it has no issue stacking ... When this parameter is on, it takes one exposure and rejects all the others. I centered on a starry field and took an exposure of 25 seconds and the second one failed as did the third etc... Then I clicked in alignment, the reset All... This turned off Optimize for Faint Stars. Now I stack perfectly..

what does that optimize do? I certainly have many faint stars in this image.
Thanks,
Marc
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Re: SC not stacking images if more than 10 seconds.

#5

Post by admin »

Hi Marc,

ah, OK, that kind of makes sense... Perhaps the naming of the option is the issue here...

'Optimize for faint stars' is designed to help when the only stars in the image are faint ones and SharpCap has trouble finding any stars at all. If you use it on a very starry area it may cause so many stars to be detected as to cause the sort of problems you are seeing, particularly if combined with a relative high sensitivity set in the star detection settings.

I will try to think of a way to re-word that setting that makes it clearer what it does (perhaps add a tooltip if it does not have one already). From your point of view though, leave it turned off unless you end up imaging areas where a lack of stars is an issue.

cheers,

Robin
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