Photo problem with Livestack

Discussion of using SharpCap for Deep Sky Imaging
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tiziano
Posts: 16
Joined: Thu Jan 10, 2019 5:42 pm

Photo problem with Livestack

Post by tiziano »

Goodmorning everyone.
I'm a beginner.
I have a problem, I have
photographed the Vega star
through SharpCap 3.2 Livestack ,I captured 161 light frames (30 minutes),and 50 Dark frames but, (for your info during the Livestack there were 30 frames not aligned), at the end after post-processing I saw that the 'VEGA star' and the other stars are Ok, (they are not moved), but in the photo you can see many of the red, green, and blue lines, (noise?, but I used the dark frames there shouldn't be), I can't understand what it is, and where is the problem, can you help me, do you have any suggestions,

sorry for my english is terrible
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admin
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Re: Photo problem with Livestack

Post by admin »

Hi,

so two issues

1) Some frames not being stacked - this is usually because SharpCap cannot detect enough stars in the image to align the frame with the previous ones - you can fix this issue by either taking longer exposures or by adjusting the settings in the 'Alignment' tab (https://docs.sharpcap.co.uk/3.2/#Alignment%20Tab)

2) Blue/Red lines - these can often be caused by hot pixels and can remain after using dark frames under a number of circumstances

* ) The dark frames used different camera settings to the light frames
* ) You have applied a very large stretch to the final image
* ) Only a small number of dark frames were captured leading to noise in the averaged dark frame

An approach to getting rid of these trails if you cannot fix them based on the above ideas is to use a more advanced technique called 'dithering' which makes small random movements to the telescope between some frames - this stops the trails from being lines and makes them less noticeable, but requires a guiding camera and application in SC 3.2

Robin
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