Go Back   IceInSpace > Equipment > Astrophotography and Imaging Equipment and Discussions

Reply
 
Thread Tools Rate Thread
  #21  
Old 19-10-2007, 08:16 PM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
Here is an image of what happens when I turn the camera off and let it get back to ambient and then turn it back on to -15C. Just a bit of frosting and look at the size of that dust mote. Compare with the second one that had been brought down slowly and allowed to slowly sublimate over about 1/2 to 3/4 of an hour
Attached Thumbnails
Click for full-size image (-15 deg screen dump.JPG)
124.0 KB17 views
Click for full-size image (-15 slow drop and sublimated.JPG)
49.2 KB14 views
Reply With Quote
  #22  
Old 20-10-2007, 07:27 AM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
Emailed SBIG last night, received and email this morning, a new ring is on the way. Pretty good service, wot!

BTW those darker marks across the first image, they are there in exactly the same position each time the glass frosts up. they are clearly visible when I look at the chip when frosted. There must be some sort of contaminant on the inside of the glass that the frost collects on.
Reply With Quote
  #23  
Old 20-10-2007, 08:01 AM
Dennis
Dazzled by the Cosmos.

Dennis is offline
 
Join Date: May 2005
Location: Brisbane
Posts: 10,916
Hah - call that an ST7 Flat??? This is a real Flat, circa 2003.

Cheers

Dennis
Attached Thumbnails
Click for full-size image (FLAT Median.jpg)
65.2 KB10 views
Reply With Quote
  #24  
Old 20-10-2007, 08:05 AM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778


How did you clean that?????
Reply With Quote
  #25  
Old 20-10-2007, 08:16 AM
Dennis
Dazzled by the Cosmos.

Dennis is offline
 
Join Date: May 2005
Location: Brisbane
Posts: 10,916
Hi Paul

I made my own swab based on this DSLR cleaning how to and used PEC pads and Eclipse cleaning fluid. Worked a charm.

Cheers

Dennis
Reply With Quote
  #26  
Old 20-10-2007, 08:20 AM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
I gather they were on the outside of the glass and not on the inside then? I'm wondering where mine is as it is so big. It must be a fair way from the chip surface.

I remember someone posting info somewhere here on how to work out where the dust is based on it's size but I can't find it now.
Reply With Quote
  #27  
Old 20-10-2007, 09:03 AM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
An interesting little animation

I was interested in seeing how long it would take for a frosted chip to clear through sublimation so I did a little experiment and here are the results.

I left the camera off for half an hour to reach room temperature and then turned it on and set the temp to -15deg C. Naturally the chip frosted over pretty much immediately. I then left the camera at -15 and took a series of images until it was clear again. It took 40 min to sublimate clear which is handy to know. Anyway here is the animation.
Attached Thumbnails
Click for full-size image (Sublimation Animation.gif)
175.9 KB27 views
Reply With Quote
  #28  
Old 20-10-2007, 10:59 AM
Dennis
Dazzled by the Cosmos.

Dennis is offline
 
Join Date: May 2005
Location: Brisbane
Posts: 10,916
Quote:
Originally Posted by [1ponders] View Post
I gather they were on the outside of the glass and not on the inside then? I'm wondering where mine is as it is so big. It must be a fair way from the chip surface.

I remember someone posting info somewhere here on how to work out where the dust is based on it's size but I can't find it now.
Hi Paul

To remove the dust motes, I removed the large, circular cover plate (including O-ring) and cleaned the glass surface on top of the ccd chip itself, as cleaning the glass window on the cover plate did not remove the marks.

Cheers

Dennis
Reply With Quote
  #29  
Old 20-10-2007, 11:06 AM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
I'd say with the size of my spot that my dust mote is on the underside of the glass coverplate. I'll give it a bit of a clean once the new O ring turns up.
Reply With Quote
  #30  
Old 22-10-2007, 04:39 PM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
Problem looks like it's fixed. I'll still have to recharge the desiccant plug again, but fingers crossed.

The first shot is 1 min @ 100% cooling immediately after it stabilized at -14C. No frosting. There is only an outer ring of frosting present. The second shot is from 5 min later and the frost has retreated considerably in that time.

Well on the way to being a very happy chappy. Once the new seal gets here I'll bake the desiccant again, while that is happening I'll replace the seal and dust the inner surface of the faceplate glass window (might replace the seal at work in the airconditioning ).
Attached Thumbnails
Click for full-size image (Image 100 percent cooling  -14 deg x 1min drop from RM temp.JPG)
47.1 KB7 views
Click for full-size image (Image 100 percent cooling  -14 deg x 1min drop from RM temp 2.JPG)
46.8 KB7 views
Reply With Quote
  #31  
Old 23-10-2007, 04:27 AM
gbeal
Registered User

gbeal is offline
 
Join Date: Oct 2004
Location: New Zealand
Posts: 4,301
Don't be a whimp Paul, like Dennis I have had the cover off the front on one of my SBIGs, it wasn't rocket science even for a Queenslander. As you say, great time to do it as well, when replacing the seal, just don't sneeze.
Reply With Quote
  #32  
Old 23-10-2007, 05:57 AM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
I'll bet the hands were shakin' just a bit though Gary

I've had the cover off already to reseat the seal, but I must admit the decision to remove the face plate wasn't made lightly that's for sure with warranty and everything.
Reply With Quote
  #33  
Old 23-10-2007, 06:12 AM
gbeal
Registered User

gbeal is offline
 
Join Date: Oct 2004
Location: New Zealand
Posts: 4,301
Shakin'? Nope, a few red wines fixed that, LOL. Really though, it wasn't all that bad. I wouldn't put up with dust just becasue of the fear of removing it though.
Reply With Quote
  #34  
Old 23-10-2007, 06:32 AM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
I won't have any fears using the fantastic Arctic Butterfly for dust removal. Works a treat on all my other cameras.
Reply With Quote
  #35  
Old 26-10-2007, 02:09 PM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
Ok problem solved (I hope permanently).

The first photo was taken on the night of the 22nd before I rebaked the desiccant. A straight drop from ambient to -14 deg in one go. You can clearly see frost around the extremities of the image. The second photo was taken this afternoon with the sweat running off me, very muggy. Ambient at about 25 deg. I dropped the camera temp straight down as far and as fast as it would go, down to just below -10 deg (mine must cool more than the stated 30 deg which is fortunate )

As you can see there is only the slightest trace of frosting in the corners (you may need to flick between the two images). There is no way I could have done this before. When the new seal comes from SBIG I'll just keep it in reserve. If this one is working it will be handy to have an unblemished spare


Added an animation
Attached Thumbnails
Click for full-size image (Image 100 percent cooling  -14 deg x 1min drop from RM temp.JPG)
47.1 KB4 views
Click for full-size image (Cooled - reading -10.5 deg histo adjusted.JPG)
108.9 KB6 views
Click for full-size image (Animation1.gif)
124.4 KB8 views
Reply With Quote
  #36  
Old 26-10-2007, 03:58 PM
Dennis
Dazzled by the Cosmos.

Dennis is offline
 
Join Date: May 2005
Location: Brisbane
Posts: 10,916
Glad to see your problem with the failing O ring will soon be fixed Paul.

Cheers

Dennis
Reply With Quote
  #37  
Old 26-10-2007, 09:42 PM
jase (Jason)
Registered User

jase is offline
 
Join Date: Sep 2006
Location: Melbourne, Victoria
Posts: 3,916
Ditto

Pleased to hear you're back on track Paul.
Reply With Quote
  #38  
Old 27-10-2007, 07:58 AM
[1ponders]'s Avatar
[1ponders] (Paul)
Retired, damn no pension

[1ponders] is offline
 
Join Date: Nov 2004
Location: Obi Obi, Qld
Posts: 18,778
Thanks guys. I've actually gotten a lot out of the experience. I certainly know my way around the CCDSoft Setup dialogu box now and feel much more comfortable with using the camera. Definately a case of "Every frosty cloud has a silver lining"
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 03:29 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2020, Jelsoft Enterprises Ltd.
Advertisement
EQ8-R
Advertisement
Astromechanics
Advertisement
Star Adventurer
Advertisement
Lunatico Astronomical
Advertisement
Bintel
Advertisement
Celestron RASA
Advertisement
Astronomy and Electronics Centre
Advertisement