Foggy eyepieces or binos

[TSRobot]

Hi. Just wondering. What do people use to stop binoculars and eyepieces dewing up. Newts don't seem to, but I have to pack it up when my eyepiece is fogged. Next I grab my binoculars, but they fogged as soon as my eyes got close the other night. Maybe the microwave?

[John]

I tend to keep my binoculars and eyepieces warmer than the outside temp. If they get too cold, when your eyes get close to the eye lenses, they can fog up from your body heat.

 

[LukeSkywatcher]

Keep EP's (when not in use) in a closed case or in a coat pocket. If they fog up due to dew whilst in use......you can just wipe them with a clean soft cotton t-shirt (if you are wearing one) or a non-lint micro fiber cloth.  However...............this should only be done if and when you are 100% sure that there is not grit or anything on the lens. If you wipe a lens with grit on it, you will most likely scratch the lens. 

Same applied for bins.

[N3ptune]

I use a heater to keep my eyepieces warmer then the ambient temperature and to keep my mirrors warmer during winter observation. Or I simply take my eyepiece in my car and start the car to reheat them.

Procedure to build a dew heater, bellow, i did it and it's a very effective device.

http://www.deepskywatch.com/Articles/newtonian-dew-heater.html

[TSRobot]

Got my eyepieces on the radiator at the mo and binos zipped inside my jacket. 24 MV is taking ages to cook. 

[John]

They just need to be kept a bit above the outside temp - not cooking !

[TSRobot]

Would a small dew band wrapped around the focusser keep the dew off eyepieces by then conducting heat to them gently?

[cjdawson]

For my camera lens, I'll use 1-3 single use hand warmers the ones that last for 10 hours.   This is more for time lapse, and I'll use 3 warmers if I think there will be dew.  Rather have a warm lens and dew in a time lapse.

For my telescope, I use a dew heater made of nichrome wire.  Works great.

The eye pieces, I keep in a closed case, if I needed to add heat, I'd put a hand warmer in the case as well.   This would be an electric one, as opposed to the single use ones.

Can also use a dew band on the eyepiece itself.

[TSRobot]

1 minute ago, cjdawson said:

For my camera lens, I'll use 1-3 single use hand warmers the ones that last for 10 hours.   This is more for time lapse, and I'll use 3 warmers if I think there will be dew.  Rather have a warm lens and dew in a time lapse.

For my telescope, I use a dew heater made of nichrome wire.  Works great.

The eye pieces, I keep in a closed case, if I needed to add heat, I'd put a hand warmer in the case as well.   This would be an electric one, as opposed to the single use ones.

Can also use a dew band on the eyepiece itself.

Hi. Thanks for your help. I've just been looking at hand held power packs which can also warm the hands and are charged by USB. Seems like a possibility to help keep all my eyepieces a bit warm. Thinking that if i put them into small cool bag that might keep them warm as cool bags are insulated.

[TSRobot]

Anybody got any ideas how to keep dew off a Rigel finder? It fogs up first now. Thought about putting a sock on it or cutting a hole in a toilet roll and fitting that somehow.

Attempt 1 in the pic.