Dewing of CCD

[ribuck]

Hi all,

I have a starlight Xpress MX916 and a Atik filter wheel. I've noticed that i've started to get small perfectly formed circles of dew on the glass of he ccd chamber behind my filters.

The odd thing is that i never see any dewing taking place on my filters, only behind them on the ccd chamber glass.

Does anyone have any idea what can be causing this or how to remmedy it.

My ccd is permanently located in my scope housed in my obs and coevered in a scope cover.

As you can see the results are horrific.

(click to enlarge)

[SteveL]

Ah, so it is dewing up, as I mentioned in your Maxim woes thread, and not an electronics glitch.

Is the condensation spot on the outside of the CCD nosepiece glass or on the inside?

[Roy]

I know this is of no help what so ever but my old SXV-M7 did exactly the same thing.

Once I'd dried it off a few times it was fine.

[jcm]

I use an SXV-M7 as a guide cam. At this time of year when I first start up sometimes condensation appears as a perfect circle on the outer surface of the glass cover. ( not inside or on the CCD). I just wipe it off or use a hair dryer. I am thinking of getting a small heater tape to solve the problem.

John

[Psychobilly]

I t may be worth putting the cams in a seled bag with some fressh silica gell bags form time to tiem as this should remove all traces of moisture.

When I did the tec cooling mod for my DSI IIC I had some dewing issues so whe i stripped it i decided to fit a couple of small packs of sillica gel inside the housing...it's been fine since...

Billy...

[Whippy]

The odd thing is that i never see any dewing taking place on my filters, only behind them on the ccd chamber glass.

Not odd at all, moisture in the air is attracted to the coldest surface and as your sensor is cooler than anything else.... If it's on the outside of the glass (so you'd be able to wipe it off), then a dew strip is your answer as I found out recently.

Personally I wouldn't keep the CCD permanently attached to the scope if dew is an issue in your obs, I'd pack it away in the case with a few silica gel packets to keep it dry.

Tony..

[Ford Prefect]

I agree with Tony and Billy, My qhy8 is stored in a small peli case with a big tin of silica. http://cgi.ebay.co.uk/*Peli-Silica-desicant-gel-For--All-Peli-Cases-*_W0QQitemZ260336407738QQcmdZViewItemQQimsxZ20081223?IMSfp=TL081223115002r25431

It doesn't always solve the problem but it happens less frequently, I also use a blinky bespoke heater strip wrapped round the nose piece of the camera

Jon

[ribuck]

Hi all Sorry for the late reply. yeah my dew is on the outside of the ccd glass as everyones has suggested. I guess i'll start bringing it my ccd into the house, and storing it in a container with some silica gel packets as my obs is not 100% moisture proof.