Placing a dew heater around the corrector cell is somewhat futile because glasses a very poor conductor of heat - the outside edge will be warm but the centre can easily be below the dew point. Better to put it some distance down the OTA to heat the air inside the OTA, and let ...
However, I had so-so results with dew heater straps for quite a long while. I just put that down to our extremely heavy dew down here in Possum Swamp. Luckily, many a long year ago somebody who knows a lot about the subject, Mr. Dew Buster himself, Ron Keating, schooled me on the...
You can buy dew heater straps in different lengths (i.e. to accomodate different circumferences). Quote 2) Will these heaters melt the rubber on eyepieces? I'd hate for that to happen, especially on a premium eyepiece. They do not get nearly hot enough to do that. They heat eyepieces...
Closed the observatory up again, turned on a 1500W oil heater and 3 dew straps, and the corrector plate got fixed in 10 minutes. However the mirror was still 99% fogged up by then. I tried pointing the scope both sides to the oil heater, moved the 3 dew straps to the mirror side,...