In South Carolina, one thing we constantly have to deal with is humidity. A low humidity day here usually means under 70%. Most nights in the spring, summer, and fall months, as the night grows older, the humidity grows higher. So with cooled CCD cameras, dew/condensation is always a constant battle. My ST-8E is quite finicky, as if it gets the least bit damp, I will get a camera timeout error, followed by a unable to connect message. This means all imaging stops until I dry it out and then re cool it. To solve my set of circumstances, I have taken a two fold approach to prevent dew and condensation from forming. This involved installing a rear dew shield, and using a "Sweat Band" for the camera. The pictures below illustrate my solution. I can now make it through the wettest of nights without losing the camera.
|If a dew shield works for the front of the scope, why not for the back. A Celestron 8" dew shield held in place by an elastic velcro band keeps the business end dew free.||A GEM never exposes its "underbelly" to the sky, so the dew shield only needs to cover the top 60% of the back end.|
|This amount of shielding keeps the dew off even if the camera needs to be rotated to frame a shot.||Protected, yet open for air circulation, this has been the best solution to date in keeping the camera and all other devices dry.|
|When working in the garden, cutting grass, or in general "manual labor" on a hot, humid Saturday afternoon, a sweatband keeps my head dry. I transferred this simple concept to my camera to control condensation.||Wrap the entire camera with a strip of towel, leaving only the vents open so air will circulate. This almost totally eliminated the condensation problem and now I can cool the camera to -25C with no bad consequences.|
Even though the Paramount has plenty of cabling for electronics "thru the mount", if you want to run a separate guider with a parallel interface, or run water cooling lines to your camera, you must run these through the mount yourself (assuming enough room and I haven't tried yet) or run them the traditional way. I added an extra plate to the back of my Versa-Plate to give the cabling better support close to the cameras to relieve stress and keep the balance constant across the sky.
|The plate helps to extend the support of the cabling out to the cameras.||Every cable now returns to a single point and makes "all sky" balancing quite easy.|
|Another view to show the routing.||Another view.|
|This also makes it easier to deal with all the cables that must be moved when rotating the camera, as it keeps the pressure off the delicate connections.||Do you think there is enough stuff back here !!|