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Is this some kind of noise?

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#1 jsowens

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Posted 18 March 2019 - 10:53 AM

So I've been making significant changes to my acquisition config & workflow.

 

Putting my latest setup to work I found some type of noise in an M101 sub that I haven't come across before.

 

Edge14", Atik460EX, Hyperstar
SQM=20.5, Trans=above av, Seeing=average, Moon @ 30%

I think the rest of the need to know stuff is in the FITS below

 

This is a single LUM lightframe Bin=1x1 zoomed in 4-5x

Autofocused using feathertouch and @focus3

 

What type of noise is this that is peppering the frame?

 

I know its just 1 sub but this is new to me.

 

 

Sub.png


Edited by jsowens, 18 March 2019 - 10:56 AM.


#2 jsowens

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Posted 18 March 2019 - 10:55 AM

fit1.jpg

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#3 Jon Rista

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Posted 18 March 2019 - 11:26 AM

Looks pretty normal to me. You've got Poisson noise (temporally and spatially random) from read noise and shot noise. You've got a slight bit of hot and cold pixels as well as some other slightly structured patterns (all FPN). The darker pixels, those can be a combination of FPN as well as just more highly deviating pixels from random noise. Note that, the RMS noise with a Poisson distribution is just one standard deviation...but pixels can deviate by more than one standard deviation. So if your RMS is say 4e-, that means ~68% of your pixels will deviate up to +-4e-, but that also means ~32% will deviate more than that. 



#4 einarin

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Posted 18 March 2019 - 12:02 PM

Looks normal.

Just need more frames and dithering.


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