Author Topic: Increased noise after calibration  (Read 1566 times)

Offline wbernhardt

  • Newcomer
  • Posts: 8
    • View Profile
Increased noise after calibration
« on: 2015 April 23 03:51:03 »
Hi,
I observed a terrible increase of noise after calibration of my lights (using bias, flats, darks). Using only darks, I do not see any difference to the raw material (there is not much noise visible). If adding bias, noise is increased, if using flats it will get dramatically worse. The flat as such looks perfect, very smooth.
What else can I check / do? What possibly did I do wrong? I used the recommended PI process published by Vicent and it works perfectly well with images taken with my refractor. Now I changed to a C 11 and I am getting trouble...
Many thanks in advance,
Wolfgang

PS I made quite some trials and figured out that if my flats are calibrated with darkflats I am getting much better results(, but I am still not happy with it) compared with bias-calibrated flats. Furthermore, if am using the "Optimize" button in "Image Calibration" for the Darks, almost nothing from my object is visible, in contrast to using none or only "calibrated". 
I wonder what I am doing wrong. I would share my snapshots with you, if I knew how to attach it to this message.
« Last Edit: 2015 April 26 13:37:53 by wbernhardt »

Offline wbernhardt

  • Newcomer
  • Posts: 8
    • View Profile
Re: Increased noise after calibration
« Reply #1 on: 2015 April 27 11:55:37 »
Hi,
while waiting for any answers I used the time to scroll through former posts - and luckily I did find what I needed: all was due to the unsigned/signed issue discussed earlier and when applying the tipps of Juan and Jim (jkmorse)/Nov 2014 I was successful in getting the desired "unnoisy" images I was looking for...! Per aspera ad astra... For a beginner like me a lot of things are well hidden, but I learned alot while trying out a lot of things - which can be fun - sometimes.
Best wishes
Wolfgang

Offline Carlos Milovic

  • PTeam Member
  • PixInsight Jedi Master
  • ******
  • Posts: 2173
  • Join the dark side... we have cookies
    • View Profile
    • http://www.astrophoto.cl
Re: Increased noise after calibration
« Reply #2 on: 2015 April 27 12:19:40 »
Glad to hear that! Sorry I missed your first post.
Regards,

Carlos Milovic F.
--------------------------------
PixInsight Project Developer
http://www.pixinsight.com

Offline llpastro

  • PixInsight Addict
  • ***
  • Posts: 193
    • View Profile
    • Sonoran Dark Skies
Re: Increased noise after calibration
« Reply #3 on: 2015 April 27 13:12:04 »
Wolfgang, would you point me to the postings that solved your problem?  Thanks in advance.

Larry
AP 140 Refractor
SBIG ST-10XME
AP Mach 1 Mount
ATS Portable Pier
Tucson, Arizona

Offline jkmorse

  • PixInsight Padawan
  • ****
  • Posts: 912
  • Two questions, Mitch . .
    • View Profile
    • Jim Morse Astronomy
Re: Increased noise after calibration
« Reply #4 on: 2015 April 27 14:34:09 »
Wolfgang,

Glad to hear my effort helped.

Best,

Jim
Really, are clear skies, low wind and no moon that much to ask for? 

New Mexico Skies Observatory
SBIG STXL 6303E w/AOX
Planewave CDK17 - Paramount MEII
Planewave IFR90 - Astrodon LRGB & NB filters
SkyX - MaximDL - ACP

http://www.jimmorse-astronomy.com
http://www.astrobin.com/users/JimMors