Thu, 01/15/2015 - 16:44

Hello all:

I am having some of my winter observing sessions cut short when the cables on the scope/camera/mount get so stiff that they start disconnecting due to torques when I slew the mount.  I've had two cables snap right off.  When I'm dismantling I can hardly get the cables in the door of the house they are so stiff.  The real problems develop when it gets down to -25C (-13F) but even at -10C I'm worried about wear and tear on my equipment.  I was wondering if anyone knows if and where cables are available for use in the cold.  I'm thinking of power supplies, USB, and the 4- and 6-connector phone-type cords used to connect hand controllers, guiders etc.  I bought a nice cold-weather extension cable from SBIG for my camera, works great - why does nobody else seem to make such cables?  I know many of you on these fora don't experience much cold, but surely there are enough Alaskans, northern States, Canadians, Scandinavians that there is some demand.

Thanks

Rick Wagner, WCR

 

Affiliation
American Association of Variable Star Observers (AAVSO)
cold weather cabling

Hi Rick, as you know, I'm also a borealite.  This year I've run my gear at below -30C, so I know what you are talking about.

The cables that Astro-Physics supplies for their mounts are flexible to low temps.  Some kind of silicone outer sleeve.  I haven't looked very hard in to sourcing that material.   I would describe their approach to design as "cost-plus", i.e. build what is right and then figure out what it has to sell for.  Rather than picking a price and figuring out how "features" they can cram in at that price by using lowest-cost materials.

AC power cords are the worst, as they are usually cheap vinyl(?) and often are stiffer than desireable even indoors.  Apple puts more thought, and $, in to their cables and power cords, but that doesn't help us here (and I haven't even tried them outside in the cold).  I've home-made a number of cables using the same materials as those SBIG extension cables that you referred to.  I.e. using regular single conductor stranded core wire inside a braided sheath.  Those work well, even though none of that material is designed for low temp.  It does take a bit of work making up such cables, but has the payback that I can make them exactly the lengths I want, and can make repairs and customizatons when needed.  I've built up a small stock of the necessary connectors (e.g. SBIG's choice of connectors are available from Mouser, but not Digi-Key, or at least last time I looked).

Making your own cables also requires a fine tip soldering iron, and a heat gun for heat-shrink tubing to finish everything off.  I generally put very small heat-shrink sleeves over all wire-to-pin solder connections, for extra mechanical strength and insurance against shorts and degradation.

I've found that USB cables aren't usually too bad, as they are small gauge.  For ethernet cables, I buy it by the 500 and 1000' box.  The kind rated for outdoor use is more flexible than the kind of meant for putting inside indoor walls (and quite a bit more expensive).  But that means I also had to buy a crimping tool, and making up those RJ-45 ends is a pain, though it does get easier with practice.  You can also use that outdoor ethernet cable for serial cable.

Sorry, but my solution mainly comes down to "building my own" cables!  And, a permanent observatory.  Even a 2'x3' shed that rolls away from the pier (post in the ground!), is a HUGE improvement.  I now have a dome, but my first "permanent observatory" was about 2'x3'.  I didn't leave the OTA+camera on, but I left the mount there, with all cables running to it.  It looked unfortunately like a privy, but my neighbours were kind about it!  It not only saved setup / alignment time, but minimized how much I had to plug/unplug frozen cables.

Good luck,   Gary Billings, Rockyford, Alberta

Affiliation
American Association of Variable Star Observers (AAVSO)
Cold weather cabling

Rick,

Being from Vermont I have also been experiencing weather below 0 F.  I do single channel PEP so I spend time both at the scope and at my computer in a small heated room in my observatory.  I have had issues with both cable and mount electronic freezeup. (As well as personal freezeup).  I don't have much experience with speciallized cold weather cables, but have attached a link to a company that specilizes in low temp wire (they are based in Alaska).  They sell both individual and multiconductor wires designed and tested for flexibility at cold temperatures.  They also sell assembled power cables.  I have attached a link to one of their power cables.  They sell both to industry and the general public.

http://store.polarwire.com/browse.cfm/power-cord-seoow-12-3-10arctic-ul…

Good luck and stay warm.  Still warmin up from my 5 hours outside last night at -1F.

Jim

 

Cold Weather Cabling

Thanks guys, both excellent information.  I'm certainly not above making my own cables and I do have some of the tools required - just need to find out where to get the cable and the connectors, and Polar Wire looks like they have a lot of what I need.

Gary - your mention of using a permanent observatory makes me realise that part of my problem is poor cable management even on the portable setup.  I need to make some arrangement so that cables only bend somewhere away from the mount and in a controlled large-radius way.  At least that would keep things working while I'm observing.

I moved to the boonies a couple of years ago and have not yet got around to building a new observatory, but I am just in the initial stages of acquiring a huge upgrade in scope/mount that, if it comes to fruition, will force me to build the observatory this spring.  Can't wait.

Rick

Affiliation
American Association of Variable Star Observers (AAVSO)
Spiral Cable Wrap

I gather my cables together and wrap them in a spiral cable wrap.  This forces the cables into a controlled radius that mostly stays away from the mount.  The bundle will also slide over projections that will catch indivual cables.

This is the stuff I'm talking about although I probably didn't use that brand.

http://www.cableorganizer.com/spiral-wrap/

Jim

Affiliation
American Association of Variable Star Observers (AAVSO)
Extension of USB

Further to the topic of cabling, I have been struggling to find a USB to CAT 6 converter to run my SBIG and mount.  I have purchased a few USB2.0 powered devices and find only the guide scope can connect.  I found a USB to wifi to work but the download speed is too slow for focusing or high cadence images.  I had a Powered USB extension working for about a year but it degraded and hard to replace behind the wall.  Any successful ideas for USB to Ethernet?

Much appriciated