Out for my first Polaris venture late this afternoon/evening. I set up while it was light, and wanted to "climates" the instrument for an hour or so before returning at dusk to take the shots...Temps weren't that low (low-mid teens), but were dropping like a rock.
The thought occurred to me though: Do the bubble vials freeze, or are they filled with mineral oil or alcohol or something? Need I worry about them if the equipment is out for hours?
I've always understood them to be filled with an alcohol solution, which is why they're called "spirit levels". I've had my gear out all day in temps as low as -30F, and never had one freeze.
No, they do not.
http://en.wikipedia.org/wiki/Spirit_level
There are other hazards to the instrument in extreme temperatures but I have little experience working below freezing so I will leave that to others.
Leica guns have a heater for extreme cold that I have never turned on, I got cold feet from the "turning on this feature will drain the battery rapidly" pop up.
Never had a vial freeze, but once in Grafenwhore (feel that shiver 82c's?)it got so damn cold that a t16 froze into a block. We were on TAC-5 I believe, calling artillery fire. We had a cool little setup were you could set up the instrument right outside the bunker and the use a poncho to cover the front opening of the bunker. The hood of the poncho was pulled out so the T16 was through the hole and the you could operate the instrument from the relative "comfort" of the now "closed" concrete bunker. Grafenwhore is in the mountains and is subject to a pretty mean temperature inversion.
Above freezing temps at altitude allow rain to fall as water, only to instantly freeze when it hits the ground... or a T16 sticking out of a bunker. A call for adjustment comes in around 3am and we're stuck with a severely frozen instrument. We scrambled for an aiming circle out of the goat for a quick sighting. It was, literally, close enough for artillery.
I hated Grafenwhore, but it makes for some of the funniest stories.
Don't get me started on the wild boar.
I've always been told they are filled with an alcohol/glycerol mix.
Neither will freeze within human tolerable conditions.
While one can push the operating temperature specifications for survey equipment to some extent, there will be a practical limit which may only be found by experience.
I recall working with a Red 2L EDM mounted on an optical theodolite many years ago where the levelling vials were fine. There was an odd clicking sound coming from the EDM however when I tried to measure a distance. The first question I got from the techical support staff was 'how cold is it?'. I estimated about -50C. The instrument was only rated to -20C. Hence it would not work. Why I was working I cannot remember....
Vials will not freeze in humanly bearable temperatures. Leica recommends 2 minutes per difference of temperature (Celcius) to acclimate. One of their model Flexline is rated to -35 Celsius, the best I have seen so far.
In the cold, in most cases:
-The total station display will be very hard to read and sluggish if the instrument is out too long in the cold.
-Batteries will be depleted if leave them in in the cold. Keep inside your jacket.
-Electronics will be fine, even leaving the gun overnight. Why would you leave the gun overnight? Broken down snowmobile and owner says "just leave it there, let's walk"
-Be careful with the cables, when putting away, grab as is and let them thaw before trying to roll them.
I worked in the cold back in my younger days, you know it's cold when your brain cannot process 45+27 as it easily does in the heat.
> In the cold, in most cases:
>
> -The total station display will be very hard to read and sluggish if the instrument is out too long in the cold.
> -Batteries will be depleted if leave them in in the cold. Keep inside your jacket.
True enough. Even with the lit LCD display, it was getting both sluggish and hard to read. Batteries in the TS held up ok, but my iPhone (time keeper)died after three rounds. Gotta remember to charge everybody up before heading out. Dropped my laptop in the snow too, but that's another matter.:-O
No they shouldn't freeze.
You might notice a difference in the size of the bubble at great temperature variations.
