If I understand you correctly

Forums Imaging Fighting Dew If I understand you correctly

Dr Paul Leyland

If I understand you correctly, the dewing is occurring between the objective and the camera.

If so, would it be possible to cut a hole in the OTA and fit a dessicator (and possibly a circulation fan to be powered up only outside observing sessions to avoid tube currents)?

Sounds brutal, I know, but that would appear to be from where you need the water removed.