Whats wrong with my ccd?

[DavidNg]

Hi, ccd images were "normal" at first, after an hour or two into the night, all images have strange dendritic marks around the oval edges. Sky was fairly clear, telescope did not appeared frost or dew. I set the SBIG ST10 at -10degree.

Could this be frost within the ccd body?

Thanks in advance.
David

[Dennis]

Looks like frost in the cd chamber. Read the SBIG manual on removing the dessicant pug, replacing it with the dummy and then baking the plug (without “O” ring!) in the oven at the SBIG specified temperature.

Cheers

Dennis

[DavidNg]

Thank you Dennis,

I will do just as your advice. As a newbie with so many things to learn, I never thought one day would need to use the desicant.

Regards

[Terry B]

I agree. It is frost.

[Dennis]

Just be careful with the oven temperature – my old ST7 manual warned that if you set the oven too high, there was a risk that the internal solder would flow!

I think I used to bake mine for approx. 3 to 4 hours at around 150 deg C but check the manual and don’t forget to remove the “O” ring before placing in the oven.

I need to bake mine maybe once per annum, due to the humidity in Queensland.

Cheers

Dennis

[[1ponders]]

:thumbsup: to what Dennis is saying David. I had similar problems with my ST7XME. I even went so far as to buy a Closet Camel and put the camera (without the dummy plug) in a large ziplock plastic bag (clothing vacuum bag) for a day beforehand. Then bake the plug and replace when cooked, put your hand in the bag (with the O ring on now ;) ) and seal the camera.

You can follow the adventure here http://www.iceinspace.com.au/forum/showthread.php?t=72044&highlight=frost

I've used the camera a couple of times since going from ambient to -30 below ambient straight from scratch without any sign of frosting. The last time was only a month or two ago

[DavidNg]

Thanks everyone for your advice.

I dont even know whats inside the metal screw and desiccant chamber or what are dummy plug and O ring. Will give them a good look tonight.

Greatly appreciated
David

[DavidNg]

Reading through the camera's manual, it shows how to regenerating the desiccant, another related question please. After heating the descicant container in the oven, should I replace back into the camera while it is still hot or wait for it to cool down?

Regards
David

[[1ponders]]

I let it cool down in the oven before putting it back. If you can handle it comfortably you can put it back in.