Dewy Eyepieces

[PN PM]

Hi.
I have a question regarding bringing eyepieces indoors, particularly when they're frosted-up or dewy. Is it best to uncap them and leave them out to air-dry?
With camera lenses the standard practise is to seal the camera and lenses in an air-tight plastic bag before bringing them into a warm environment.
For ten years now I have been following the former procedure of uncapping/airdrying, but I always wonder if there might be a better way!
Any suggestions?

[Waxing_Gibbous]

Hi Lynn,
Welcome to IIS.
I grew up in Vancouver so I know all about dew. ;)
If you're getting dew-free EPs, then I would stick with your current method. Some people blow them with a hair-dryer (on low heat) but I'm too lazy!
I use the same method as you but give the EP a good shake to get any excess moisture off. I also have been known to actually WIPE mine with a lens cloth from time to time. I know the produces apoplexy in purists, but the coatings and glass and pretty hard and unless you're EPs are covered in dust, you are highly unlikely to do any harm.
Keeping them warm in the scope is another option. Electric eyepiece dew-busters are available from Kendrick and Dew-Not, though I would think they'd be a bit fussy unless you were sticking to one EP.
A heated EP case is another, but that necessitates lugging a power source around with you.
In short the 'cap & dry' method is probably the easiest, and I know of no other that will produce better results.
Standing on guard...
Peter

[ballaratdragons]

When I use EP's and they get dewy, or very wet, I leave them uncapped inside the house over night to let them air dry.
It is the way I was taught and I've never had a problem doing it this way.
Works for me.

Leaving the caps on wet EP's can induce mold growth on the glass, and even worse, inside the EP.

[PN PM]

Good to know. Thanks for the input.

[mental4astro]

There is one other way of keeping eyepieces warm in the EP box (whatever you carry them in): thermos of hot water and a hot water bottle.

A little hot water in the bottle, capped nice and tight!!! and placed in the EP box. Might need changing the water every couple of hours or so, but it really works to keep the EPs warm.

I do use a dew zapping system for my big dob. It does complicate things, but when everyone is out of business due to dew, I'm still going. There was frost on my truss poles the last time. Optics - just fine!

Just something you need to decide for yourself.

[PN PM]

Ok. This all sounds good.

A while ago I read something about not letting moisture sit on the lens as "acid-dew" could (over time) eat away the lens' coatings. When I look at eyepieces I've had for a long time, they look...uneaten! So I guess I shouldn't worry about it too much. :thanx:

[ballaratdragons]

Optics coatings are more robust than people think.

But Aeroguard will strip them. NEVER spray aerosols anywhere near a scope!
Pete (exfso) had $5000 damage done to his Takahashi when it picked up stray Aeroguard spray at Camp 2 years ago. The Aeroguard actually ate into the glass!!!
The scope had to go back to Japan to have it's primary lens replaced. $5000 plus freight both ways.

BEWARE of aerosols!

[jenchris]

You mean insect spray?... ate the lens...
EEK

[ballaratdragons]

Yep. Imagine what it does to us when we inhale it :eyepop:

Aerosols are banned on the observing field at our Camps.
Roll-ons are OK.

[PN PM]

Wow, I wonder how much aerosol spray is used to do that much damage? (Not that I want to try.)
At the camp where this happened, I wonder if the damage was done outside or in an enclosed space.

[Suzy]

Ken, does the same apply to coils or the lamps that have the repellent candles in them?