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

Deep Sky Stacker and M8: only 7 images processed out of... 240!

  • Please log in to reply
3 replies to this topic

#1 kurtenstein

kurtenstein

    Vostok 1

  • -----
  • topic starter
  • Posts: 129
  • Joined: 28 Sep 2018
  • Loc: Montréal

Posted 09 July 2020 - 07:28 PM

Hi! I'm an AP noob trying to figure something out. I chose the Lagoon Nebula as a target. I used a Fujifilm X-T20,a vintage 135mm f3.5 Super Takumar on a manually operated barn door tracker (type 1) to take 240 3-second exposures, for a planned total of 12 minutes. (ISO 1000) Using Deep Sky Stacker, I processed those images and added 10 darks and 10 offsets. 10 flats were planned... but I forgot to shine a light through my white fabric, so those were left behind.

 

Problem is... the final TIFF file in DSS doesn't seem much nicer than the indiviudual RAF (Fuji RAWs) files. M8 does stand out a bit more, but not that much. What annoys me the most is the fact that, at the end on the stacking process (it took hours!), it seems that only 7 images were stacked! [I use the French version, in case you wonder.]

 

 
DSS 7 images

 



#2 jgraham

jgraham

    ISS

  • *****
  • Posts: 21,090
  • Joined: 02 Dec 2004
  • Loc: Miami Valley Astronomical Society

Posted 09 July 2020 - 08:22 PM

This happens if DSS has trouble locating alignment stars in the field. Try turning the sensitivity up by turning the threshold down. The default is 10%; try 5% or even 2%. If that fails try rescaling the images 50% to reduce the size of the stars.



#3 kurtenstein

kurtenstein

    Vostok 1

  • -----
  • topic starter
  • Posts: 129
  • Joined: 28 Sep 2018
  • Loc: Montréal

Posted 10 July 2020 - 08:45 AM

This happens if DSS has trouble locating alignment stars in the field. Try turning the sensitivity up by turning the threshold down. The default is 10%; try 5% or even 2%. If that fails try rescaling the images 50% to reduce the size of the stars.

Thanks! I'll try to turn the treshold down. Rescaling... the 240 pictures? Is there a way to do that at once? (Remember: I'm new to this...)



#4 MHamburg

MHamburg

    Vanguard

  • *****
  • Posts: 2,022
  • Joined: 21 Jun 2006
  • Loc: Brooklyn, NY/Berkshires, MA

Posted 10 July 2020 - 05:45 PM

Often DSS will reject stars that are not well-focused as well. This has happened to me, too.

Michael




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






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics