Accessories - Clothes
Good warm clothing is essential for late fall, winter and early spring observing. However, regular clothes do not keep warmth well enough for me to last long outside on a freezing Northeast nights, and the all required layers of clothing become heavy and inconvenient. Because of that I turned my attention to heated clothes, but most places offer just battery-powered clothes that won't last long, and they don't offer complete sets - usually vests only. After some research I found that one of the most respected companies specializing in heated clothes is Gerbing. They sell 12V externally powered sets of clothes to motorcyclists, snowmobilers, hunters and others that require reliable long lasting heat when sitting still for long in the cold (sounds familiar ?).
I chose their heated liners - they are light and do not restrict freedom of movement, while the heated outdoor clothes are much more rigid. The entire set of clothes connects together via special plugs and sockets, that look similar to a regular power supply plugs. The set requires only one external connection, an optional power regulator to control level of heating and a cable forking to two plugs. Both plugs plug to two sockets in the jacket's three socket panel, pants plug to the third socket, gloves and socks plug to the sleeves.
Originally the set comes with a typical cigarette lighter 12V plug, but the cable is way too short for moving around the observatory and on the deck. I bough a short Gerbing extension cable, cut the female side off and connected it to a 25' heavy duty extension cord: I cut the end of the cord, soldered the cables together and used some epoxy to make it completely waterproof. I cut the other side of the extension cord and attached a plug for 12V AC to DC converter. The clothes use quite a lot of power at maximum heat, so I bought RadioShack 12V AC/DC converter rated for 15A (13.8VDC 15-Amp Power Supply).
It works extraordinarily well and I very happy with it! I have been using it for two winters already - and I still believe it is an essential piece of my astro equipment. I don't need to wear that much clothing on cold nights anymore, just three layers: underpants and blouse underneath, heated liners and then snow pants and a coat. I can stay observing as long as I want, even when temperature drops to teens (F) and lower. 25' extension cord is more than enough to move around and it doesn't restrict me much. I highly recommend this solution to anyone observing in a place with an access to power!