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

Reply
 
Thread Tools Rate Thread
  #1  
Old 12-01-2014, 11:32 AM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
QHY9 - how to change dessicant.

I have a QHY9 mono camera.
I don't have any problems with it.
It works perfectly.

I have Google searched and been to the QHY site but can't find answers to some basic questions.

Questions:

(1) I have been wondering how to change the desiccant inside the camera?
I have a packet of desiccant strips.

(2) There are 2 screws on the back & I believe one or both needs to be unscrewed?

(3) Why are there 2 screws?

I know there is argon inside the camera to prevent dew forming.
(4) I don't know whether this argon is inside the whole camera or just in the sealed optical chamber?

I can find no picture on the internet showing how to change the desiccant.
The instruction manual has no pictures.
(5) are there any photos or videos available?

(6) Can opening one of the screws cause humid air to go inside & cause a problem?

(7) Should it be only performed on a dry day - low humidity?

(8) Should it really be done only if you have argon available &
performed inside an argon filled plastic bag?

(9) If I need argon where would I purchase it?



Hopefully someone will know the answers.

cheers
Allan
Reply With Quote
  #2  
Old 12-01-2014, 11:40 AM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Here's a photo from the manual.
I believe that screws 7 & 8 are the ones for the desiccant strip?
Attached Thumbnails
Click for full-size image (QHY9.jpg)
150.2 KB48 views
Reply With Quote
  #3  
Old 12-01-2014, 11:54 AM
RobF's Avatar
RobF (Rob)
Mostly harmless...

RobF is offline
 
Join Date: Jul 2008
Location: Brisbane, Australia
Posts: 5,411
Hi Allan

Best info is probably to PM Theo - he's on top of everything, but the meantime:

1. Theo put some adhesive backed desiccant strips in my camera. You have to take off the main body screws to get at those.

2. 7 and 8 have rubber o-ring seals, and a couple of uses I'm aware of:
(a) Can purge the camera with argon etc using these as ports
(b) You can buy (or may have received) a metal desiccant tube that screws into one of these - I keep mine attached to camera permanently with cut up desiccant inside I replace every few months rather than opening camera. Here's a pic:
http://www.google.com.au/imgres?um=1...d=0CJsBEK0DMBY

3. as per (a) - better for purging I believe

4. Not sure - Theo best for comment - suspect not - probably just assembled in clean and dry environment - any argo filler would eventually escape with time

5. Might be worth taking back off camera to see if your desicccant is double side adhesive. There is no rechargeable pouch etc ala SBIG I'm aware of - just the desiccant tube on exterior option

6. Opening camera can of course. Do you have an air conditioned room you could use - just that bit dryer. Inner chamber is the most critical as long as you do a ramped cool down and warm up each use. Unlikely you'd get much moisture through the screws in a few mins?

7. Low humidity day would help (or having air con on perhaps)

8. I put desiccant and argon in mine. You can buy small disposable argon cylinders and valve sets at Bunnings in the tools section. I've read a post on IIS somewhere where Theo talked about getting a large plastic bag of argon from local welding shop and doing assembly in the large bag. I find purging after having camera open works well.



The only time I've even been BAD with my camera was when it was new and I didn't have all the filters and spacers. I ran the camera without the 12mm window a number of times, along with fiddling with it (open to atmosphere) in damp dewy summer conditions (while trying filters, MPCCs, spacers etc - stuff I should have done at home, not in the field, armed with 20/20 hindsight). I then had problems with moisture inside the camera, but not the optical chamber.


Nowadays I would never open the camera in a damp environment and not without changing desiccants. I got the impression from Theo argon is an extra generally unnecessary step, but once you have a small cylinder its no big deal. We've got 500L of liquid argon at work, but I've always wondered how the heck I could get any of it home to play with
Reply With Quote
  #4  
Old 12-01-2014, 12:12 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Quote:
Originally Posted by RobF View Post
Hi Allan

Best info is probably to PM Theo - he's on top of everything, but the meantime:

1. Theo put some adhesive backed desiccant strips in my camera. You have to take off the main body screws to get at those.

2. 7 and 8 have rubber o-ring seals, and a couple of uses I'm aware of:
(a) Can purge the camera with argon etc using these as ports
(b) You can buy (or may have received) a metal desiccant tube that screws into one of these - I keep mine attached to camera permanently with cut up desiccant inside I replace every few months rather than opening camera. Here's a pic:
http://www.google.com.au/imgres?um=1...d=0CJsBEK0DMBY

3. as per (a) - better for purging I believe

4. Not sure - Theo best for comment - suspect not - probably just assembled in clean and dry environment - any argo filler would eventually escape with time

5. Might be worth taking back off camera to see if your desicccant is double side adhesive. There is no rechargeable pouch etc ala SBIG I'm aware of - just the desiccant tube on exterior option

6. Opening camera can of course. Do you have an air conditioned room you could use - just that bit dryer. Inner chamber is the most critical as long as you do a ramped cool down and warm up each use. Unlikely you'd get much moisture through the screws in a few mins?

7. Low humidity day would help (or having air con on perhaps)

8. I put desiccant and argon in mine. You can buy small disposable argon cylinders and valve sets at Bunnings in the tools section. I've read a post on IIS somewhere where Theo talked about getting a large plastic bag of argon from local welding shop and doing assembly in the large bag. I find purging after having camera open works well.



The only time I've even been BAD with my camera was when it was new and I didn't have all the filters and spacers. I ran the camera without the 12mm window a number of times, along with fiddling with it (open to atmosphere) in damp dewy summer conditions (while trying filters, MPCCs, spacers etc - stuff I should have done at home, not in the field, armed with 20/20 hindsight). I then had problems with moisture inside the camera, but not the optical chamber.


Nowadays I would never open the camera in a damp environment and not without changing desiccants. I got the impression from Theo argon is an extra generally unnecessary step, but once you have a small cylinder its no big deal. We've got 500L of liquid argon at work, but I've always wondered how the heck I could get any of it home to play with
Hi Rob,
Thanks for your reply.

So you're saying that I can remove one of those screws & it should be attached to a barrel shaped device?

I can then take out the desiccant from inside that barrel
& replace it with another piece of dessicant?
I have a little packet with about 20 rectangular shapes of desiccant strip.
I assume that I cut one into a thin strip & put it inside the barrel?

Would I do the same for both barrels?

The whole instruction manual is here:
http://qhyccd.com/ccdbbs/index.php?a....0;attach=1820

& is so confusing that I can't make head nor tail of it.
e.g.
the manual says:
Quote:
7) Air socket port. M5 Europe standard (Used for Gas purging)
8) Air socket port. M5 Europe standard (Used for Gas purging)
But doesn't say if screws 7 & 8 are connected to a barrel shape device for desiccant change &
who is supposed to be doing gas purging - what gas? - & how to do that?

I don't really want to pull the whole back off the camera.
I like to leave well alone.

cheers
Allan

Last edited by alpal; 12-01-2014 at 12:24 PM.
Reply With Quote
  #5  
Old 12-01-2014, 12:24 PM
RobF's Avatar
RobF (Rob)
Mostly harmless...

RobF is offline
 
Join Date: Jul 2008
Location: Brisbane, Australia
Posts: 5,411
The desiccant barrel has the same thread as the screws and actually replaces one of them. it screws on to the outside of the camera and is about 5cm long (bit less than depth of camera). I leave mine installed all the time - no problem as you're always being gentle on the camera anyway.

The strips you describe sound like what I've purchased off Theo before. I'm not sure if they're adhesive. Believe theo sometimes attaches adhesive desiccant inside the camera himself in strategic locations. Would have to peel off, clean adhesive then reattach new if going that route.


If you don't like opening the camera, might be worth getting a metal plug unit off theo and looking at argon purging for 6 months to annual maintenance.
Reply With Quote
  #6  
Old 12-01-2014, 12:33 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Quote:
Originally Posted by RobF View Post
The desiccant barrel has the same thread as the screws and actually replaces one of them. it screws on to the outside of the camera and is about 5cm long (bit less than depth of camera). I leave mine installed all the time - no problem as you're always being gentle on the camera anyway.

The strips you describe sound like what I've purchased off Theo before. I'm not sure if they're adhesive. Believe theo sometimes attaches adhesive desiccant inside the camera himself in strategic locations. Would have to peel off, clean adhesive then reattach new if going that route.


If you don't like opening the camera, might be worth getting a metal plug unit off theo and looking at argon purging for 6 months to annual maintenance.

Thanks Rob,
The barrel is attached on the outside of the camera?
OK - just looked - I do have a barrel & 2 little plugs inside a plastic packet.

So I need to unscrew one of the screws & attach that barrel to the outside of the camera?
The barrel could be easily broken off couldn't it?

To be safe -
I'd really need to open the camera & replace the plastic strips that Theo has probably put inside it?

Wow - If only a simple picture had been provided.
This is nothing like what I imagined.

regards
Allan
Reply With Quote
  #7  
Old 12-01-2014, 12:40 PM
RobF's Avatar
RobF (Rob)
Mostly harmless...

RobF is offline
 
Join Date: Jul 2008
Location: Brisbane, Australia
Posts: 5,411
Yep - replaces one of those 2 screws (7 and 8) and screws on OUTSIDE. Its tougher than you think once screwed on, but agree care needed if left installed. My concern is that its a relatively small aperture into the camera for the desiccant to be acting, so I put some argon in as well.

At the end of the day both strategies would seem to only be as good as the seal on the camera chamber (there is a single large o-ring seal).
Reply With Quote
  #8  
Old 12-01-2014, 12:49 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Quote:
Originally Posted by RobF View Post
Yep - replaces one of those 2 screws (7 and 8) and screws on OUTSIDE. Its tougher than you think once screwed on, but agree care needed if left installed. My concern is that its a relatively small aperture into the camera for the desiccant to be acting, so I put some argon in as well.

At the end of the day both strategies would seem to only be as good as the seal on the camera chamber (there is a single large o-ring seal).
Ok Rob,
thanks for clearing up all that confusion which would have been saved by a single picture.

I'll tell you what -
I will be the first person to publish such a picture on the internet to help everyone else.
I am sure I'm not the only one who has ever been confused.

I don't have any dew problems but it was about time I added some desiccant.

cheers
Allan
Reply With Quote
  #9  
Old 12-01-2014, 01:01 PM
Ken
Registered User

Ken is offline
 
Join Date: Dec 2005
Location: Mount Olive via Singleton
Posts: 332
I have owned a qhy9 since they were first released and unlike other ccd cameras I have owned sbig st6 and qhy8 this camera has never had any dewing problems. I think the heater on the shutter board contributes a lot to keep things dry.
Clear Skies Ken.
Reply With Quote
  #10  
Old 12-01-2014, 01:29 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Quote:
Originally Posted by Ken View Post
I have owned a qhy9 since they were first released and unlike other ccd cameras I have owned sbig st6 and qhy8 this camera has never had any dewing problems. I think the heater on the shutter board contributes a lot to keep things dry.
Clear Skies Ken.
That's good news Ken.
I have had no problems either.
I do cool down & allow it to heat back up very slowly which might help.

Anyway - finally a picture!
I just did it - so simple when you know how.
Attached Thumbnails
Click for full-size image (QHY9 dessicant.jpg)
159.6 KB59 views
Reply With Quote
  #11  
Old 12-01-2014, 05:19 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Quote:
Originally Posted by RobF View Post

The strips you describe sound like what I've purchased off Theo before. I'm not sure if they're adhesive. Believe theo sometimes attaches adhesive desiccant inside the camera himself in strategic locations. Would have to peel off, clean adhesive then reattach new if going that route.


If you don't like opening the camera, might be worth getting a metal plug unit off theo and looking at argon purging for 6 months to annual maintenance.
Hi Rob,
Just a few more questions for you or anyone else?

The desiccant strips have plastic each side of them.
When I tried to peel the plastic off it left me with just
a thin layer of what looked like cardboard each side.
Does that sound correct to you?
I expected to see a layer of only desiccant.
I had to cut the strip shorter to fit inside the tube.

Also - where can I buy just a little spray can of argon?


cheers
Allan
Reply With Quote
  #12  
Old 12-01-2014, 06:46 PM
coldlegs's Avatar
coldlegs (Stephen)
Chopped its rear end off!

coldlegs is offline
 
Join Date: Jul 2009
Location: adelaide, sth aust
Posts: 330
Alan
I've had some problems with QHY9M dewing mainly due to accidentally unscrewing the front glass due to tight threads and exposing the inners the the outside air. What I do is get a very large thick clear zip lock bag and put the camera inside along with the front glass and a fresh 500g bag of desiccant. Zip it up and leave it for 48 hours to absorb all the moisture. Then I carefully screw the front glass on whilst it is still inside the bag. It always works. The desiccant can be easily found on Ebay like this one..
http://www.ebay.com.au/itm/4x-500-gm...7420350&_uhb=1

To refresh it simply put it in the oven at 120C for about 2-3 hours and put it in the bag whilst still warm.
Cheers
Stephen
Reply With Quote
  #13  
Old 12-01-2014, 07:46 PM
RobF's Avatar
RobF (Rob)
Mostly harmless...

RobF is offline
 
Join Date: Jul 2008
Location: Brisbane, Australia
Posts: 5,411
Quote:
Originally Posted by alpal View Post
Hi Rob,
Just a few more questions for you or anyone else?

The desiccant strips have plastic each side of them.
When I tried to peel the plastic off it left me with just
a thin layer of what looked like cardboard each side.
Does that sound correct to you?
I expected to see a layer of only desiccant.
I had to cut the strip shorter to fit inside the tube.

Also - where can I buy just a little spray can of argon?


cheers
Allan
Actually, I'd be interested to hear what other people say about this Allan. I currently peel the plastic off each side - my logic is to increase the surface area exposed to internal environment. Happy to be told I'm wrong by someone who knows better. I put quite a few small cut up pieces in the tube. They do eventually seem to swell and get a little thicker.

Argon in disposable cylinder is about $39 at Bunnings. I saw one there this afternoon in the Tool shop when looking for something else. Just ask the guys. You'll have to buy a cheap screw in valve assembly too - I just put the plastic pipe up against the camera.

Putting the camera in a large bag with desiccant for storage is something I used to do too. Leaving the barrel on just seems to make more sense rather than having it sit in the box
Reply With Quote
  #14  
Old 12-01-2014, 08:43 PM
multiweb's Avatar
multiweb (Marc)
ze frogginator

multiweb is offline
 
Join Date: Oct 2007
Location: Hinchinbrook
Posts: 17,836
I have two gel tubes on each side. Filled with pink/blue beads that I microwave for 10s before I use the camera. At the bottom of the tubes I have a thin slice of foam so the beads don't fall into the camera. I also store my QHY9 open in the sealed box after use and purge it with Argon every time I use it.
Reply With Quote
  #15  
Old 12-01-2014, 09:31 PM
mill's Avatar
mill (Martin)
sword collector

mill is offline
 
Join Date: Oct 2006
Location: Mount Evelyn
Posts: 2,922
Hmm it looks like most people get a bit hung up on this desiccant and Argon purging.
I haven't had any desiccant strips in my QHY9 for some years and i open it in my living room and close it in my living room (no bag).
Since i removed the desiccant strip some years ago, i have had no problems anymore with dew or water in the camera.
I had problems with the desiccant strip and corroded legs on the sensor because of this.
The strip becomes saturated and releases water that has to go somewhere.
It starts acting as one of those water traps you use to keep closets dry.
I run the camera without the front glass and no desiccant and have no dew or moisture inside the camera for years.
Your mileage may vary doing it this way but it works for me.
Reply With Quote
  #16  
Old 12-01-2014, 10:20 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Quote:
Originally Posted by coldlegs View Post
Alan
I've had some problems with QHY9M dewing mainly due to accidentally unscrewing the front glass due to tight threads and exposing the inners the the outside air. What I do is get a very large thick clear zip lock bag and put the camera inside along with the front glass and a fresh 500g bag of desiccant. Zip it up and leave it for 48 hours to absorb all the moisture. Then I carefully screw the front glass on whilst it is still inside the bag. It always works. The desiccant can be easily found on Ebay like this one..
http://www.ebay.com.au/itm/4x-500-gm...7420350&_uhb=1

To refresh it simply put it in the oven at 120C for about 2-3 hours and put it in the bag whilst still warm.
Cheers
Stephen
Thanks Stephen,
I'll know what to do if I ever have a dew problem.
Reply With Quote
  #17  
Old 12-01-2014, 10:24 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Quote:
Originally Posted by RobF View Post
Actually, I'd be interested to hear what other people say about this Allan. I currently peel the plastic off each side - my logic is to increase the surface area exposed to internal environment. Happy to be told I'm wrong by someone who knows better. I put quite a few small cut up pieces in the tube. They do eventually seem to swell and get a little thicker.

Argon in disposable cylinder is about $39 at Bunnings. I saw one there this afternoon in the Tool shop when looking for something else. Just ask the guys. You'll have to buy a cheap screw in valve assembly too - I just put the plastic pipe up against the camera.

Putting the camera in a large bag with desiccant for storage is something I used to do too. Leaving the barrel on just seems to make more sense rather than having it sit in the box
Hi Rob,
Thanks for that.
OK - so I'll check the desiccant in about a week & see if it has swollen.

Great news that Bunnings has cans of argon.
I already have 2 little adaptor screws in the same bag that the barrel was supplied in.
Hopefully the Bunnings argon is free of water.
Some good tips - thanks.

cheers
Allan
Reply With Quote
  #18  
Old 12-01-2014, 10:27 PM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Quote:
Originally Posted by mill View Post
Hmm it looks like most people get a bit hung up on this desiccant and Argon purging.
I haven't had any desiccant strips in my QHY9 for some years and i open it in my living room and close it in my living room (no bag).
Since i removed the desiccant strip some years ago, i have had no problems anymore with dew or water in the camera.
I had problems with the desiccant strip and corroded legs on the sensor because of this.
The strip becomes saturated and releases water that has to go somewhere.
It starts acting as one of those water traps you use to keep closets dry.
I run the camera without the front glass and no desiccant and have no dew or moisture inside the camera for years.
Your mileage may vary doing it this way but it works for me.

Hi Martin,
I haven't used desiccant until today & have had no problems either
but then again Melbourne is very dry.
I am just trying to do the right thing to look after my investment.
I will check & change the desiccant regularly so that it does not
get saturated with water.

cheers
Allan
Reply With Quote
  #19  
Old 12-01-2014, 11:57 PM
RobF's Avatar
RobF (Rob)
Mostly harmless...

RobF is offline
 
Join Date: Jul 2008
Location: Brisbane, Australia
Posts: 5,411
I'm flat out seeing much change in my desiccant strips over months usually Allan. I keep the camera closed all the time and charged with argon every month or so when I'm using it regularly.

I wouldn't expect you'll see any swelling over a week or so unless you're running it without the front window in dewy conditions.
Reply With Quote
  #20  
Old 13-01-2014, 12:09 AM
alpal's Avatar
alpal
Registered User

alpal is offline
 
Join Date: Jan 2012
Location: Melbourne
Posts: 2,778
Quote:
Originally Posted by RobF View Post
I'm flat out seeing much change in my desiccant strips over months usually Allan. I keep the camera closed all the time and charged with argon every month or so when I'm using it regularly.

I wouldn't expect you'll see any swelling over a week or so unless you're running it without the front window in dewy conditions.

Hi Rob,
No - I never take the front window off.
I think I'll buy that argon anyway.

This forum is so good.
I found a solution for something that had nagged me for a long time
as the instruction manual had too many holes in it.

cheers
Allan
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 09:02 AM.

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