I built a 12v heated case from an electronic coffee mug,copper tubing, a Celestron accessory case, and a project box from radio shack. This thing works great! I do most of my observing on or around beaches so early morning dew & frost is A HUGE problem for me. When one Ep falls victim, a warmer one is ready to take its place.
http://i22.photobucket.com/albums/b3...Heatedcase.jpg