I can't be the only one!! Fogging up eyepieces.

[Andrew*]

I'm being seriously hindered this evening by a very strange problem.

Eyepieces fogging up when I put my eye to them. What I have now resorted to is holding a hairdryer in one hand and blowing the eyepiece, looking for 10 seconds, blowing again, looking.... Not convenient.

I put all the rest of the eyepieces in my pocket to warm up, but it's a matter of minutes before these act the same when I try to use them!

Others must experience the same problem! If so, what do you do about it?

I need a new set of cold eyes...

Andrew

[GazOC]

Are you breathing on them?

[Whippy]

Andrew, this happens to me a lot (including this evening). The effects seem to lessen if you breath through your nose (ie: downwards) so less warm air hits the eyepiece. Bucket-loads of air moisture here tonight so the the glow from streetlamps is almost reaching the zenith!

That reminds me, I must re-wire my power supply so I can use the normal ciggy-lighter plugs (like the hairdryer!)

Tony..

[The Warthog]

I often hold my bare hand around the top of the ep to warm it, and change eps frequently, putting the wet ones in an inside pocket. Some people use heater strips.

[spacemonkey]

A Kendrick eyepiece heater strap is the way to go -

http://www.kendrickastro.com/astro/dewremover.html

I use a 2" one which fits perfectly around a 35mm Panoptic, so is more than long enough for all my other eyepieces. I've never had an eyepeice dew up when using it.

It's a pain when you change eyepieces, but I suppose if you got a strap for each of your most used ones and kept them near the scope it might help.

Dave

[richmace]

I didn't get fogged-up eyepieces this evening, but it feels like there is fog coming in from the west...

I can see a decent amount of stars (just about pick out the whole of Ursa Minor for example - don't always manage that), but the views through the scope are dissapointing this evening.

I even had trouble getting Saturn into any kind of focus too...

The Cassiopeia / Perseus double cluster was very unimpressive - I was blown away by this two days ago.

Looks like the wonderful clear skies are dissapearing from the South-West Bath area

[Andrew*]

Cheers for the replies!

Are you breathing on them?

No, I hold my breath until my eye is up to the eye lens.

Andrew, this happens to me a lot (including this evening). The effects seem to lessen if you breath through your nose (ie: downwards) so less warm air hits the eyepiece. Bucket-loads of air moisture here tonight so the the glow from streetlamps is almost reaching the zenith!

It did depend how far away my eye was, and to an extent how I breathed. My biggest problem came from the Nagler, which only has 10mm eye relief. On the Meades, I extended the eye guard and had little problem with them. No fog here tonight, but plenty of frost raining down.

I often hold my bare hand around the top of the ep to warm it, and change eps frequently, putting the wet ones in an inside pocket. Some people use heater strips.

Tried both, and unfortunately it did little to help. The eyepiece would cool down again very quickly and the fog would come back. Tried a dew strip on the Nagler zoom, but it meant I couldn't zoom because the strip was too wide :insects1:...

A Kendrick eyepiece heater strap is the way to go -

I need some more 1.25/2" ones to use for some eyepieces. If there was a really narrow one that would fit around just the front section of the Nagler zoom I think it would solve it!

Thanks again

Andrew

[Talitha]

Our hot little eyeballs kick out a lot of moisture, don't they? :?

Heat tapes work, but not as well as I'd hoped they would. Well, actually they work pretty good if you use the same ep for a long time, but depending on what my target is and what scope I'm using, the ep's can get changed pretty often and they never get a chance to warm up properly.

I've found a few ways to keep the fog down to a minimum, though:

1) Constantly fan the air on the ep with your hand or something.

2) Position yourself so that any slight breeze present will drift between your eye and the ep. Most of the time this means you can't look at what you want to, but it tends to keep the ep clean.

3) Warm the ep inside of a vest pocket till it's used, but this method only lasts till the glass cools down again.

4) Keep your eyes closed. :laughing6:

[Vega]

Yep, I get this problem too. Another thing worth checking is your secondary mirror (if u use a Newt). I hairdryed my eyepiece to find I was still getting a murkey blob view. I took out the 1.25" ep holder to see a VERY fogged up secondary mirror in behind. A quick blast of the hairdryer very quickly disolved the fog. (Mirrors seem to de-fog much quicker than lenses).

I think some astro-zap might be added to my infinate 'wanted' list

Matt

[James]

An Astrozap dewshield works for me Matt - haven't had a dewed up secondary since I got one!

Eyepieces ocasionally fog when I use them, it tends to be when I'm wearing a balaclava or my coat is zipped all the way up so whenever I exhale some of my breath bounces back up to the eyepiece. I also try the holding of breath thing before looking through the eyepiece after hyperventilating for a few seconds before hand which helps but not every time.

James

[Vega]

Thanks James, I did a home made dew shield which was overkill and kept falling off (used a cut up thermal camping matt which looks ugly). Just the push I needed to convince me to buy one of those neat looking astrozap one's. Would that be the 10" LXD or SCT one's?

Re: EP fogging

Maybe a snorkle will do the trick....

Even better, full firemans BA kit & oxygen cylinders

[SteelRat]

I put all the rest of the eyepieces in my pocket to warm up, but it's a matter of minutes before these act the same when I try to use them!

:shock:

Where do you keep your eyepieces during the day?

[James]

Would that be the 10" LXD or SCT one's?

I think I got the 10" LXD one. Fits well enough (certainly hasn't fallen off yet except when I put it on an 11" scope :? )

Re: EP fogging

Maybe a snorkle will do the trick....

Even better, full firemans BA kit & oxygen cylinders

It'll certainly keep you nice and warm...

James

[alfingido]

Correct me if I`m wrong here, ( I usually am) but putting them in a pocket / keeping them warm ( eyepieces) means that when out in the cold, on the scope, they are going to fog up because the glass is warmer than the surrounding air....condensation?

I dont think I have ever had an eyepiece fog up quickly, I take my eyepieces out in a semi shut case at the same time as the scope so they all cool down at the same time and are the same temp when I start viewing.

Allan

[James]

I thought condensation comes from warm air hitting cold objects not the other way round which is presumably why we spend so much time trying to keep out optics slightly warmer than the air temperature?

My eyepieces only fog up when they've gotten really cold and then I breathe near them.

James

[alfingido]

See, I knew I was wrong, and you, of course are right.... but, I still keep mine cold. I havent really got an answer have I. I think I`ll open another bottle of wine till my telescope cools down, and wait for the clouds to appear.....

Allan