Fogging up of an eyepiece in colder weather?

[bikerdib]

I used to have a dew strap for my 14" SCT (the worst about dewing up) but after I made some foam extensions for the aluminum dew shields I use, I no longer used it and it has been sold. I made extensions for my 14", my 9.25" and my 80mm refractor. The others already have long enough tubes in front of the mirrors or lenses that dew isn't a big issue. So now, my scope's optics stay dew free until the moisture becomes incredibly bad. I'm talking water dripping off the outside of the OTA. I deal with night time humidity around 80% all the way up to 100%. In the summer the air temp seldom reaches the dewpoint but because it is always humid, things still get damp.

I do still have one issue though. In the winter on cool nights the high humidity causes the exit lens of the eyepieces to fog up from the proximity of my eye/face. I know there are dew straps made for eyepieces but unless you just use one eyepiece for the entire session, I can't see that working very well. I have heard of some people having a warming box for their eyepiece collection then using a dew strap. That seems a good solution but I'm wondering if there is others that you may have found. Right now, I usually just sit back and use my hand to fan some air across the eyepiece until the moisture evaporates.

[j.gardavsky]

Hello Dennis,

fogging of the eye lens in the eyepiece is a frequently encountered problem. Tthere are a few ways to circumvent it.
1. Eyepieces with a very long eye relief, like 20mm
2. Using the spotting scope eyepieces with the antifog multicoatings
3. Treatment of the eyelens with the Nikon Fog Eliminator wet tissues

On the cold nights I take the eyepieces ad 1. and 2.
Otherwise, I have the Nikon Fog eliminator in reserve.

Best,

JG

[bikerdib]

Thanks JG.

1. Since I have scopes that range from short FL to long FL I have spent years buying, testing, replacing, shopping, replacing and buying again to put togeather a set of eyepieces with a wide range of FL consisting of TV Naglers and 82° ES and the full range of TV Plossels. This adds up to well over $5500. I'm not looking to start over. I could get just a few but again, I need a pretty wide range because of the scopes I have. I choose the scope for a session depending on my intended targets.

2. Are spotting scope eyepieces interchangeable? What about the quality?

3. Now that is something worth considering. Four and a half decades of observing and I never knew such a thing existed. I'm not sure about it though. Cleaning eyepieces is not unheard of but I generally avoid touching my optics unless absolutely necessary. I'll check into it though. Thanks.

[bikerdib]

This look interesting: radiant

[j.gardavsky]

Hello Dennis my old friend!

Since about 2010, I have been collecting on the 2nd hand market the spotting eyepieces:
first fro Swarovski, then Zeiss (Diascope), and finally Leica (old Televid), and then together with the new APO Televid the ultrawide aspheric zoom.
They are all great performers for the astronomy: 1st place Leica, 2nd place Zeiss, 3rd place Swarovski

Should I again start this hobby, my EPs arsenal would be pretty small:
Leica WW Asph. zoom 25x - 50x (9mm - 18mm) Leica Zoom WW 25x – 50x ASPH and barlowed against the Pentax SMC XW 3.5mm
Baader VIP Barlow 2x for that Leica zoom
Leica HC Plan S 10x (25mm) and Leica L 8x (32mm) for the large faint Sharpless, Lynds and DWB nebulae
Leica HC PLAN S 10x/22 (Br.) M, focusable, f=25mm Eyepiece, item #507807

The Leica zoom requires adapter bayonet-to-1.25", available at APM.
The Leica HC Plan S compares well with the legendary discontinued Zeiss E-Pl, I also have. The 30mm nose tube is easily adapted to 1.25" with the old black canister for the Kodak films.

When some money is left, then the Docter is worth of having, DOCTER completing my ultrawide arsenal

There is a narrative on CN describing, how Mark Ludes came to a star party in the U.S. with the Leica zoom in one pocket
and with the Docter in the other, and has sold the both during that star party. They did not let him leave with the both EPs he wanted just show.

Best,

JG

[bikerdib]

Yes JG, I have looked at your eyepiece collection. You know what I'm talking about when I say buying and replacing. You have some, shall we say, unusual items there too.

I'm looking into using some sort of case warming. I keep all my eyepieces capped and in bolt cases inside the case. This takes up less room but also offers more protection for the eyepieces. I could add some warming and I think that would help. I have a 12 volt hair dryer that I keep handy. If an eyepiece I'm using and want to continue to use, a quick warming would probably help.

But I'm still looking for suggestions. Never know what someone has come up with.

BTW, it appears the Nikon xry wipe clots have been discontinued.

[j.gardavsky]

Hello Dennis,

I have still a pack of the old ones I've got from a friend in the U.S., but maybe there are some replacements
https://www.amazon.com/gp/offer-list...&condition=new
as they find use on the rifle scopes.

Otherwise, I keep the EPs on the cold nights in the heat isolating old Fuji and Minolta bags.

Best,

JG

[refractordude]

I keep my eyepieces in a very small cooler with a hand warmer.

[rickg18704]

This look interesting: radiant

Thanks Dennis. I'm taking a proactive approach to dew prevention this year and this product looks like it suits my needs.

[bikerdib]

I keep my eyepieces in a very small cooler with a hand warmer.

Nice solution. My problem is I have too many eyepieces to do a transfer each time. Do you worry about any sort of outgassing with the chemical warmers? I have no clue if they do or not.

Thanks Dennis. I'm taking a proactive approach to dew prevention this year and this product looks like it suits my needs.

I'm really leaning towards one myself.