#1  
Old 03-11-2016, 08:07 PM
rogerg's Avatar
rogerg (Roger)
Registered User

rogerg is offline
 
Join Date: Feb 2006
Location: Perth, Western Australia
Posts: 4,542
Question "rain" dark noise?!

Hi all,

Can anyone advise on what causes this kind of noise? The length of the "rain" increases with exposure time. 1s shows no "trails", 300s shows longer trails. This example is 180s.

This is a single 180s dark frame.

ST10-XME.

Regards,
Roger.
Attached Thumbnails
Click for full-size image (2016-11-03 18_05_56-Clipboard.jpg)
96.3 KB60 views
Reply With Quote
  #2  
Old 03-11-2016, 08:12 PM
RB's Avatar
RB (Andrew)
Moderator

RB is offline
 
Join Date: Aug 2005
Posts: 22,017
Quote:
Originally Posted by rogerg View Post
Hi all,

Can anyone advise on what causes this kind of noise? The length of the "rain" increases with exposure time. Regards,
Roger.
Did you check the weather Roger?

Reply With Quote
  #3  
Old 03-11-2016, 08:24 PM
glend (Glen)
Registered User

glend is offline
 
Join Date: Jun 2013
Location: Lake Macquarie
Posts: 5,348
Heat. Camera sensors need to be cooled. The longer the exposure the more heat is generated. You may be able to subtract it with dark calibration.
Reply With Quote
  #4  
Old 03-11-2016, 08:28 PM
rogerg's Avatar
rogerg (Roger)
Registered User

rogerg is offline
 
Join Date: Feb 2006
Location: Perth, Western Australia
Posts: 4,542
Quote:
Originally Posted by RB View Post
Did you check the weather Roger?

Is that a sarcastic comment or am I missing the meaning?

Quote:
Originally Posted by glend View Post
Heat. Camera sensors need to be cooled. The longer the exposure the more heat is generated. You may be able to subtract it with dark calibration.
This is the dark. Normally I see point like noise on darks and cosmic rays, not vertical lines that get shorter towards the top of the image. Are you suggesting this a normal dark frame for some cameras?
Reply With Quote
  #5  
Old 03-11-2016, 08:46 PM
billdan's Avatar
billdan (Bill)
Registered User

billdan is offline
 
Join Date: Mar 2012
Location: Narangba, SE QLD
Posts: 1,346
Looks like the TEC cooler is not working. Attached is a crop of a single 300sec dark from my QHY12.

Bill
Attached Thumbnails
Click for full-size image (Dark-1-300s-0-C0-crop.jpg)
189.0 KB27 views
Reply With Quote
  #6  
Old 03-11-2016, 08:53 PM
rogerg's Avatar
rogerg (Roger)
Registered User

rogerg is offline
 
Join Date: Feb 2006
Location: Perth, Western Australia
Posts: 4,542
Quote:
Originally Posted by billdan View Post
Looks like the TEC cooler is not working. Attached is a crop of a single 300sec dark from my QHY12.

Bill
That is more what I am used to from my other cameras Would be a pain if the cooler has died. It is reporting a temperature and power as though it's working.
Reply With Quote
  #7  
Old 03-11-2016, 08:55 PM
billdan's Avatar
billdan (Bill)
Registered User

billdan is offline
 
Join Date: Mar 2012
Location: Narangba, SE QLD
Posts: 1,346
You may have to email SBIG and attach the image and see what they say.

EDIT: Wonder if it is noise on the USB cable?
Reply With Quote
  #8  
Old 03-11-2016, 09:42 PM
rogerg's Avatar
rogerg (Roger)
Registered User

rogerg is offline
 
Join Date: Feb 2006
Location: Perth, Western Australia
Posts: 4,542
Quote:
Originally Posted by billdan View Post
You may have to email SBIG and attach the image and see what they say.
I've posted a thread.

Quote:
Originally Posted by billdan View Post
EDIT: Wonder if it is noise on the USB cable?
We have other issues with noise on the USB cable but i"m hesitant to blame this on it .... because it's so consistent, but I could be wrong.
Reply With Quote
  #9  
Old 04-11-2016, 06:35 AM
PeterM's Avatar
PeterM
towards 2000 posts-slowly

PeterM is offline
 
Join Date: Jun 2006
Location: SE Qld
Posts: 1,608
Have you changed anything in the chain that delivers power to the camera? Month ago at Leyburn I used a cig lighter board with multiple sockets it allowed me run one wire to batteries and plug everything in at scope but it introduced very odd patterns in my ccd image. Also I had an issue some time ago I traced to the usb cable. I bought a Lindy powered usb and that fixed it.
Reply With Quote
  #10  
Old 04-11-2016, 09:55 AM
rogerg's Avatar
rogerg (Roger)
Registered User

rogerg is offline
 
Join Date: Feb 2006
Location: Perth, Western Australia
Posts: 4,542
Quote:
Originally Posted by PeterM View Post
Have you changed anything in the chain that delivers power to the camera? Month ago at Leyburn I used a cig lighter board with multiple sockets it allowed me run one wire to batteries and plug everything in at scope but it introduced very odd patterns in my ccd image. Also I had an issue some time ago I traced to the usb cable. I bought a Lindy powered usb and that fixed it.
Thanks Peter. It certainly would be worth connecting it directly to a laptop/pc with a short different USB cable. I'll see if I can arrange that.
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 10:38 PM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
OzScopes Authorised Dealer
Advertisement
Meade Australia
Advertisement
Lunatico Astronomical
Advertisement
Celestron Australia
Advertisement
Astromechanics
Advertisement
Bintel
Advertisement
SkyWatcher Australia
Advertisement
Astronomy and Electronics Centre
Advertisement