[Shiraz (Ray)]

I found that putting aluminium foil tape over the external surfaces helped a lot. This reflective material stops everything from heading for -30C due to radiative cooling from the sky - with an extension to the tube, the scope stays close to ambient inside and out and a little bit of fan forced airflow over a 2w heater and into the base of the OTA does the rest. Have also found that using an al foil shield around the focuser/filter wheel helps. Rarely have any dew problems on the scope, but everything else ends up dripping wet - part of the fun of being by the sea..

For comparison, when I first got the scope, dewing with the native CF finish was so bad that some of the internal paint dissolved in the layer of water and dripped down the inside of the tube and a bit on the mirror - modified tube doesn't look CF sexy anymore, but dew is really no longer an issue at all.