30+inch+F3+Dew+Heaters

Dew heaters are mandatory for observing in the UK. Most nights suffer from dew. The image below shows the rear dew heaters for the 30 inch F3 primary.

These are 4W heater matts from RS (RS number 245-590). A matrix of 7 are used. 1 in the middle and 6 near the edge. 28W total.



The secondary has a single 4W heater on the rear. These proved to be very effective at the recent Kelling Heath star party (September 2015) where the 30 inch F3 prototype was displayed and used.

Initially when the heaters are turned on a print through pattern can be seen. This disappears after an hour when the optic thermalizes. No effect from these could then be seen in the defocussed star at the eyepiece.

At first light at the Kelling Heath star party 2015, no dew formed on the optics all night. Yet the telescope was soaking wet from dew!