11 replies to this topic

[rboe]

I was looking at the Ranger and Pronto (bought the Pronto) and noticed that there was a fair amount of lub in the helical focuser. Personel experience with cold and lub tell me that is the source of your problem. Stuff turns to glue!

I think we have some northern Ranger owners that can recommend a good cold weather lub. I've used Break-Free with great success back in Minnesota on throttle cables. In some cases removing all lube is your only recourse (when it is extremely cold - but what the heck are you doing out then anyway? ).

[imjeffp]

There is also metal shrinkage during freezing temps

I read that as mental shrinkage...

[Cow Jazz]

Living in Toronto (as in Canada), we deal with extreme cold all to often. The answer is to remove all the grease that is currently on your focuser (and any other part of your scope and/or mount that is affected by cold temps), and replace it with a white lithium grease such as used for snowmobiles, etc. We get ours at Canadian Tire in small tubes (you don't need much), but you should be able to find it at either auto or marine supply stores. It is much cleaner, and simply works. I rebuilt my EQ5/CG5 mount with this, and the improvement was immediately obvious at all temperatures. Now if I could find a way to keep myself functioning in the cold, I'd do a lot more winter observing (snowmobile outfits are standard issue for Canadian astronomers...looks kind of silly, but it's better that freezing your **** off!).
Let me know if this solves your problems.
John

[rboe]

I was thinking 20 below zero F. That will shrink your knickers.

[Cow Jazz]

Scott,
As far as I'm concerned, -20 is cold no matter what the scale, C or F!
Where in the NE do you live?
John

[rboe]

2) Below 20 degrees F is not -20 degrees F, it +19 degrees through 0 degrees, which is my absolute limit for telescope use.

I remember when 20 degrees was not all that bad. But I had to be moving. 50 degrees and just sitting is hard to take now.

[Cow Jazz]

Scott,
You can use any degreaser-type product (even gasoline, but that's WAY to dangerous for my tastes) such as terpentine, paint cleaner/thinner, etc. You can find some ideas by going to www.astronomyboy.com and looking at the instructions for cleaning and rebuilding the EQ5 mount.
John