Eyepiece cooldown?

iceman (Mike) · #1 28-03-2005, 07:46 PM

Hey guys.

Last week I got my first piece of serious glass, my new Meade UWA 14mm.. It's only had 10 minutes of first light last night, every other night has been cloudy/rainy, and even last night there was a big bright thing in the sky which washed out everything I tried to look at.

So can't judge it much at the moment, compared it to my 15mm GSO plossl and with the bright moon the two main things I noticed better in the UWA were the much wider FOV, and sharpness to near the edge.

Just a quick question though, with a seriously large and heavy eyepiece like that (and I imagine like the naglers etc), with so many lenses in it, does it need time to cooldown and reach ambient temperature?
Will it perform better after it's been outside for a little while? Just wondering whether I should open my eyepiece case up to cooldown at the same time I open my scope up to cooldown..

Thanks

Dave47tuc (David) · #2 28-03-2005, 07:59 PM

Mike,
Hope you like the 14mm

and get to use it more soon.

You will find the big glass eyepieces cool down to much in winter. Kendrick actually sell dew straps for 2" eyepieces.

You can find dew or fogging on your eyepiece more of a problem.
I use a small 12v haid dryer for this problem.

I would not concern yourself with this one to much.

As long as the eyepiece has not been in a hot car or under to much temperature change, use it and it will be fine.

jackenau · #3 28-03-2005, 08:19 PM

Evening Mike.

I have found that with the larger eyepieces they behave better (better viewing, especially towards the outer perimeter), when let out to cool down.

ie have left my dob outside for in excess of 2 hours and then used an ep that was left inside. Poor viewing. However within at least an hour or so the viewing improved. Maybe its all in the mind.

Ken M

ving (David) · #4 28-03-2005, 08:52 PM

on ya mike. poor viewing has hit me since getting my TV too... makes it hard to tell just how good it is

ballaratdragons (Ken) · #5 28-03-2005, 11:01 PM

I have to recommend cooling of large EP's. Why? Coz my GS 2" SV has seagulls until it has cooled for about a half hour. After cooling I have no problems.

I find that it fogs easily when first taken outside too. Once cooled I have not had a problem with fogging either.

Mike, I don't leave the case wide open or leave the EP in the open air for cooling. I take the 2" out of it's cardboard box and let it sit in the EP box with the lid of the EP box open about 1" (2.5cm).

Works for me anyway.

RAJAH235 · #6 28-03-2005, 11:11 PM

Mike, I've never had a problem with mine, other than picking it up!
Just use it and put back in plastic container.

L.

ballaratdragons (Ken) · #7 28-03-2005, 11:38 PM

Just thought of a critical point.

I live in a very cold area and Mike doesn't. Maybe you won't have to have a cool down time Mike.

My temp difference from inside to outside is currently about 20 degrees.

janoskiss (Steve H) · #8 29-03-2005, 12:10 AM

I agree with Ken, the GSO SV (30mm) does seem to benefit from cooldown (more stars less seagulls). Indoor/outdoor temp diff ~10 degrees.

iceman (Mike) · #9 30-03-2005, 01:28 PM

Thanks guys for the feedback, will experiment a bit with it and see how it performs under both.

rumples riot · #10 30-03-2005, 07:04 PM

Mike I usually take my case out at the same time and open the carry case. The plastic case will cool down slowly and you should have no trouble with it. Being on the coast as you are, you should not have a lot of touble during the cooler months as the temp will stay pretty even during the night and day transition.