Hi Pepper

It looks like you've got the dew heater around the wrong end as the guys have already said.

When there is lots of dew, the front glass element (the corrector lens) loses heat faster than the rest of the scope, so dew builds up on the corrector and if fogs up.

The dew heater is intended to raise the temperature just enough that the dew evaporates and doesn't condense on the corrector plate.

Dew shields (like that on my NexStar 6SE) have to have a notch cut in them if the mounting bracket (as in the ETX-LS) or the dovetail (in the case of my 6SE) protrudes out of the side of the scope where the corrector lens is.

On my ETX-105, the dew shield screws into the front of the corrector (where the metal lens cap screws in), so it isn't a problem with the ETX-105 (or the ETX-90 or ETX-125 for that matter).

Hope this helps

Art