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Old 13-04-2008, 06:58 AM
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DSI cleaning experience

I finally had a go at removing an annoying dust spot on my DSI yesterday using the instructions posted on the Meade forum. It didn't turn out very well and I now have a very messy looking CCD.

Anyone got any advice?
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  #2  
Old 13-04-2008, 07:06 AM
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[1ponders] (Paul)
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Hi Peter, could you post the process that you used?
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Old 13-04-2008, 07:23 AM
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Paul,

I wiped surface with cotton tip moistened with mixture of 25% iso-propanol and 75% water. Then dried with clean dry cotton tip. The image looks like there are fine droplets remaining. What do you think?

Peter
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Old 13-04-2008, 09:42 AM
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[1ponders] (Paul)
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Can you get hold of 100% isoprop? It won't hurt the glass and if there were any oils in the original mixture (even though they are shown as being in there, there probably was. ) that should lift it off. Were they unoiled, unscented, non-cosmetic, dirt cheap, no name pure cotton tips?

Now I don't know about these new fandangle DSI pro cameras, I only have the original, but I can't get to the surface of my chip without pulling the camera apart. There is a class window that seals the camera. So if this is the case for yours then you won't have damaged the chip or get any Iso/water residue on the chip. And from the look of your dust donuts they seem to be a fair way above the actual chip, so this seems to confirm that. If they were actually on the chip the donuts would be nice and dark and sharp edged.

While your doing your cleaning did you also do the IR filter that comes with the camera? What sort of state is that in?

As long as it's only dust and dirt that is on the chip even looking like it does won't be a problem. Taking good quality flats would remove these smudges without difficulty. The problem occurs if there are oils smeared on the glass. This will bend and smear incoming light in a way the flats won't be able to deal with. If it is oily smear you will most likely find you will have problems getting a good sharp focus and that stars will have prismatic halos around them.

All is not lost though, try the 100% iso and see if that helps. If it doesn't then come on up to Ron's at the next dark sky night and I'll bring along my magic goanna oil (bintel UHTC corrector cleaner ) and we can give that a go.

I guess the secret here is if you have dust don't wet clean, unless it's really really bad and you can't blow it off with a puffer bulb.
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Old 13-04-2008, 10:20 AM
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Paul,

Thanks for the advice. I think this camera has the glass cover you describe and I know what you mean about getting to the surface as it is recessed in the DSI casing. I had contemplated pulling it apart however thought I might end up doing more damage. The image I posted was without the UV/IR filter attached.

I have some 100% Isoprop and I was using just pure cotton tips (Swisspers) though not sure if they are oiled or not.

I give what you suggest a try and if that doesn't work I'll take you up on the goanna oil offer - I'll bring my tool kit!

Peter
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Old 13-04-2008, 01:18 PM
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Give the window a clean with the Iso. If that doesn't fix it bring it up, we'll open it up and and we'll give it the once over with my Arctic Butterfly.
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Old 13-04-2008, 03:01 PM
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Thanks Paul - will do. I almost got an AB on Saturday before I got into the isoprop but they didn't have any in stock - should have waited but that dust spot was p___ing me off.

That will teach me to be impatient.
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Old 13-04-2008, 05:05 PM
Alchemy (Clive)
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probably a bit late as it could be more than just dust by now , but i bought a super duper fine artists brush with extremely soft fine bristles... one gentle swipe across the chip has always done the job for me.
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