Canon CCD - does it have to have filter/glass????

[The Thing]

Can someone tell me if I have to have the filter/piece of glass in place to use my 350d. I have it in pieces to clean the annoying mark left by frost at the infamous campsite best forgotten. The front of the CCD is now spotless but I can't seem to get the glass clean, it's al smeary. I am using Visible Dust sensor cleaning swabs and fluid.

TIA

Duncan

[Carole]

Andy at Astronomiser told me you don't need it for Astro-imaging but you'd have problems with focus I think it was for photography with a normal lens. 

Carole

[The Thing]

Thanks Carole, that's what I thought. However I found some Otpi-clear polymer in my camera bag and that really does leave optics perfectly clean. You paint it on and when cured, peel it off.

[The Thing]

Camera all back together and working. A quick flat inspected on the camera shows only a small dust bunny top right, probably fixable with a quick sensor clean.

I had a nasty moment when I had a little silver screw left over -the only silver screws hold the CCD in. However it was one I lost last time that had got lodged somewhere and fell out this time! Result. I wasn't looking forward to dismantling the thing again.