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So, we finally got a clear night, so the scope was swiftly brought out. Even tho the sky was clear it seemed very hazy. 1st stop was Jupiter but couldn't get it very clear at all,confirming the poor quality air. So we decided to look at clusters for the rest of the night.

Things we're going great, so much so we forgot about dinner. Quick run to the chip shop sorted that out tho ;) Once we had done we went back out to find all the eyepieces had dewwed up. The scopes lens was fine, just the EPs were effected. So not knowing what to do we packed up and just looked up with the naked eye and enjoyed the clear night.

So, what, if anything, can be done to remedy this problem. I've read about dew heaters/shields, but are these not more for the primary lens/mirror? Or is it just a case of admitting defeat that the night was not the right one for scoping?

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Try and keep the eyepieces at a slightly warmer temperature than the outside air. If the eyepieces get cold they can mist up as your eye (which is warm) gets close to them. I keep mine in a foam lined case with the lid closed as much as possible. This seems to keep the eyepieces just a little warmer. An alternative is to keep the eyepieces in a pocket. 

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I have had the same problem, the corrector plate stays clear, my telrad is all toasty and snug with its little electric blanket under a home made cover but the eyepiece tends to fog up quite quickly on the inside so an eyepiece dew heater tape is next on my accessory hit list.

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Ok, thanks for the replies. I'll keep them in my case on dewy nights from now on, see if that helps. Tonight was the first still night I had been out with the scope, a taste of wind seems to keep the dew at bay more.

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Keep them in the (clean & empty) pockets of your coat. One per pocket. This seems to keep them just warm enough to stave off the dew.

Sadly this doesn't work for the secondary....

Paul

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Keeping the caps on until they are needed helps for me and it's especially important to cap everything before bringing indoors, otherwise the optics dew up in seconds and I have to wait ages for them to dry before storing.

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You should have put it in the fish and chips until you had finished! Inside a chip resistant bag of course.

You can make dew heaters for very little cost but it's all adding to the complication of the setup. You need power (12v usually) plus connecting wires to the heater(s) and ideally some sort of control circuit.

I found that there wasn't enough room to fit a heater around the focuser when using 1.25" EPs so I think Paul73's suggestion is about right.

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I had a great night from the pocket tip. Dust Caps on and in the pocket, seemed to work better than the case.

Cheers for the advise.

I've seen a tip in this moths sky at night mag about building little heaters, trip to RS in order.

Clear Skys

Mike

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