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Re: No alignment found!

Posted: Tue Jan 29, 2019 9:20 am
by festoon
Hi Robin,
Last night was finally a clear evening, and I managed to try stacking again but this time using Sharpcap 3.2
I had no issues getting stacking work with this software version, so whatever is different between the two version certainly helped :)
Thank you again for your support :) !!!

Re: No alignment found!

Posted: Tue Jan 29, 2019 5:12 pm
by admin
Good to hear it's all working now!

Cheers, Robin

Re: No alignment found!

Posted: Thu Mar 07, 2019 2:11 am
by 39N84W
I can't for the life of me figure out why I'm getting randomly ignored frames. No clouds, it just happens here and there. "No alignment found" yet I've got hundreds of stars and plenty of frames that are stacking.
??
no alignment found, random.JPG
no alignment found, random.JPG (190.79 KiB) Viewed 661 times

Re: No alignment found!

Posted: Thu Mar 07, 2019 1:12 pm
by 39N84W
I've also found (and I'm not alone in this observation) that if I do anything else on my observatory laptop (surf the net, etc) I get even more ignored frames.
???

Re: No alignment found!

Posted: Thu Mar 07, 2019 5:28 pm
by MrAstroBen
Watching those late night internet videos uses the last of your processing power then.

Re: No alignment found!

Posted: Thu Mar 07, 2019 5:33 pm
by 39N84W
I'm not watching videos and I don't appreciate your humor.
I've run Infinity and Starlight Live (with dark frame subtraction) without these "ignored frame" problems.

Re: No alignment found!

Posted: Thu Mar 07, 2019 6:13 pm
by MrAstroBen
Your Astro computer or laptop should not be used for anything other than that single purpose.

Unless required for remote access it should not be connected to the internet.

Experienced imagers keep to this basic rule for good reason.

What would the head of NASA say if an employee was caught surfing the net on the launch pad computer?

Re: No alignment found!

Posted: Thu Mar 07, 2019 9:23 pm
by admin
When you are stacking high-resolution images, the amount of processing power needed to detect the stars in the image, find the alignment, translate or rotate the new image, and stack is quite considerable. If the processing hasn't finished on a previous frame when the next frame arrives then SharpCap has no option but to drop the next frame. Naturally there is a bigger chance of doing this if the computer is busy doing something else as well as processing the stack.

It's worth checking the log tab of the life stacking window if you are getting ignored frames to see what the exact reason is. You can also look in the status tab where it will list the amount of time being taken to do the various processing steps for each frame that arrives. If this time is starting to approach the exposure length of your frames then you could be in trouble from a speed point of view and you might be better off taking longer exposure subframes.

If you are getting intermittent failures to align it is almost certainly down to star detection problems – perhaps too many stars in some cases meaning that the stars selected from each frame to perform the alignment may not have a good overlap with the stars selected from the existing stack. It may be worth increasing the minimum star width parameter to reduce the number of stars detected (limit it to the brighter stars). Aim to get the number of detected stars down to maybe 50 to 100 and see if that helps.

Cheers, Robin

PS.please try to keep to the generally respectful and light-hearted tone of the forums. Thank you

Re: No alignment found!

Posted: Thu Mar 07, 2019 11:03 pm
by 39N84W
Thank you for your mature and informed response Robin. I will aim for fewer stars next time. Did not know SC likes 50-100 stars.