I had the idea of keeping my eyepieces warm in the colder, dewy weather since last winter (my first observing), and have worked up a heated eyepiece box.
The idea was to fit a heater strap inside a closed box and keep my eyepieces toasty warm (OK, a few degrees above ambient anyway).
I checked with John Marstiller at AFAB, the manufacturers of Dew-Not heating gear and he agreed that just laying a heater strap inside an enclosed space should work.
So I built a box and fitted it with a rack for my eyepieces. A rather rough wooden box, screwed together, but commensurate with my skills and functional, though not pretty. Plenty of measuring up to ensure there was sufficient space below the rack, particularly for the 10" dia heater strap to stand on end, but also for the protruding eyepiece and barlow barrels, including space for any fitted filters. Also space above the rack up to the lid for eyepiece height, including any 1.25" eyepiece in the 1.25"-->2" adapter. I added a bit of felt stripping around the edge of the lid, mainly to stop the lid banging noisily in the quiet of an observing night. A couple of eyepieces (my most commonly used 2" and 1.25") would have individual heater straps since they stay out the most. I filed some grooves in the top of the box for the heater cords to exit away to the Thousand Oaks four channel controller. I'll probably mount the controller on the side of the box (velcro) (The controller will also power a finderscope objective heater and a heater on the secondary mirror - maximum load on the power supply, everything on 100% is around 2A.)
Attached are some photos showing the result. There is sufficient space to remove the long heater strap. (I have ideas of wrapping it around my 100mm Binocular field lenses when I'm on a binocular evening.)
Now to test it out in dewy and/or cold conditions.
My intention is to mount the box at a height above the scope where I can easily access eyepieces while I'm sitting on my observing chair. I plan to simultaneously use the mount to provide a brace between the two walls of the base on which the scope sits, to keep try and stabilise the setup in preparation for a future time when I reinstall the encoders and purchase an ArgoNavis. (Yes, I know I will have to fit the brace/mount after the scope is in place and remove it to remove the scope from the base. Working on the best way to do this quickly.)
Thanks to Peter Read at SDM telescopes for prompt supply of the Dew-Not heaters and Thousand Oaks controller.
So far, so good. Eric
