Jump to content

  •  

CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.

Photo

Abundant Noise When Capturing With SGP

astrophotography beginner
  • Please log in to reply
4 replies to this topic

#1 Yogurthawk

Yogurthawk

    Explorer 1

  • *****
  • topic starter
  • Posts: 56
  • Joined: 05 Jun 2019
  • Loc: Gilbert, AZ

Posted 05 April 2020 - 05:29 AM

Hi everyone,

 

I'm about a year into astrophotography at this point, and I have always used sharpcap for image acquisition but I recently have made the switch to Sequence Generator Pro. The main reason being that I would like to use dithering in my sessions. The only problem is that when I look at the data captured from my camera (ZWO ASI1600), there is an incredibly significant increase in noise (in the form of hot pixels) all over my images vs when I use sharpcap to capture data. I really don't understand what the cause of this might be, as I make sure to cool the camera to -15C every session. Do any of you have some ideas as to what I may be doing wrong? I can link to some sample images if that helps. 



#2 Varnius

Varnius

    Lift Off

  • -----
  • Posts: 15
  • Joined: 26 Jun 2018

Posted 05 April 2020 - 05:45 AM

The amount of hot pixels should not be dependant of the software used for capture. How are you comparing the images? Maybe you are just viewing them with different stretches applied and those hot pixels are present in images captures with both apps but maybe less visible in a less stretched preview mode. Also, even having some 50k of hot/cold pixels is not uncommon and easily correctable with Pixinsight (or other processing software).

 

You can also read this:
https://www.cloudyni...-pixels-at-20c/



#3 S.Boerner

S.Boerner

    Apollo

  • *****
  • Posts: 1,444
  • Joined: 29 Apr 2010
  • Loc: Chesterfield, MO

Posted 05 April 2020 - 06:44 AM

Do you capture darks and apply a master dark in SharpCap?  If so, are you comparing the stacked SharpCap image with frames that you'd calibrated and stacked from SGP?



#4 Yogurthawk

Yogurthawk

    Explorer 1

  • *****
  • topic starter
  • Posts: 56
  • Joined: 05 Jun 2019
  • Loc: Gilbert, AZ

Posted 05 April 2020 - 06:09 PM

The amount of hot pixels should not be dependant of the software used for capture. How are you comparing the images? Maybe you are just viewing them with different stretches applied and those hot pixels are present in images captures with both apps but maybe less visible in a less stretched preview mode. Also, even having some 50k of hot/cold pixels is not uncommon and easily correctable with Pixinsight (or other processing software).

 

You can also read this:
https://www.cloudyni...-pixels-at-20c/

I'm putting the images into pixinsight and doing an autostretch. 



#5 Yogurthawk

Yogurthawk

    Explorer 1

  • *****
  • topic starter
  • Posts: 56
  • Joined: 05 Jun 2019
  • Loc: Gilbert, AZ

Posted 05 April 2020 - 06:09 PM

Do you capture darks and apply a master dark in SharpCap?  If so, are you comparing the stacked SharpCap image with frames that you'd calibrated and stacked from SGP?

I'm strictly comparing uncalibrated images. No master dark that gets subtracted in Sharpcap or in SGP.




CNers have asked about a donation box for Cloudy Nights over the years, so here you go. Donation is not required by any means, so please enjoy your stay.


Recent Topics





Also tagged with one or more of these keywords: astrophotography, beginner



Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics