Binoculars and extreme temperatures

[Griever]

Hey stargazers, 

I recently got a hold of some 15x63 mini giants, and I took em out for a first try not too long ago and was blown away at how much I could see with these, even in so much light pollution...I certainly didnt expect to see my first nebula's in downtown montreal with a pair of binoculars  

That said, when I got back home, I got a little worried at how cold it actually was (about -20c). I know most of the tricks for preventing condensation, never have the temperature change happen too quickly, the zip lock bag trick etc... But I decided to research a bit more and I found little bits of info about how extreme cold might make the casing and lenses shrink a bit, which would throw the optics out of alignment permanently...

Now I'm unsure if I can go out there and enjoy my new bins without worrying... There was very little info about this effect on binoculars, and I was hoping that maybe some people on this forum might have some info on this.

Thanks          

[BinocularSky]

Griever, when I lived in Calgary for a year, I had my binos out in temperatures at least as low as -35*C and possibly colder. The only issue I had was that focusing and right eyepiece dioptre adjustment became hellishly stiff. No permanent damage that I noticed. That said, this may well vary from binocular to binocular, so ask the manufacturer what they specify as a minimum temp. FWIW, I have never seen a stated minimum temperature higher than -20*C (but that may be because, if it is lower, they prefer not to state it) and the UO BA*s that many of us use are rated from -40*C to +70*C, not that I would trust Chinese "lubricant" not to lose viscosity and seep into the optics at anything over around 55*C (and 60*C is too hot to touch for long anyway).

[Griever]

Griever, when I lived in Calgary for a year, I had my binos out in temperatures at least as low as -35*C and possibly colder. The only issue I had was that focusing and right eyepiece dioptre adjustment became hellishly stiff. No permanent damage that I noticed. That said, this may well vary from binocular to binocular, so ask the manufacturer what they specify as a minimum temp. FWIW, I have never seen a stated minimum temperature higher than -20*C (but that may be because, if it is lower, they prefer not to state it) and the UO BA*s that many of us use are rated from -40*C to +70*C, not that I would trust Chinese "lubricant" not to lose viscosity and seep into the optics at anything over around 55*C (and 60*C is too hot to touch for long anyway).

great, thanks! The orion bins i have now all seem to be japanese parts, and I wasnt having an issue with the lubricant after being in -20c for a while, so I guess I should be ok on that end. I might try and contact them just to make sure, but i thought id ask here if anyone had some horror stories of having purchased expensive bins that failed on them because of cold temperature warping the casing. If yours managed in -35c without a problem, I dont see why I should worry. 

Thanks

[Griever]

great, thanks! The orion bins i have now all seem to be japanese parts, and I wasnt having an issue with the lubricant after being in -20c for a while, so I guess I should be ok on that end. I might try and contact them just to make sure, but i thought id ask here if anyone had some horror stories of having purchased expensive bins that failed on them because of cold temperature warping the casing. If yours managed in -35c without a problem, I dont see why I should worry. 

Thanks

In the event that someone else with a similar question comes upon this thread, I contacted Orion and they said that theres absolutely nothing to worry about when it comes to the optics, that condensation is really the #1 thing to be attentive of. Time to get some use out of these bins ~

[Joe_L]

I've had no probs at -25 apart from when a slight gust of wind made my eye water and the tear froze instantly to the bins.