[alistairsam]

Hi,

I have a 10inch F4 Truss that I use for Imaging and the other night, it was completely clear, but very humid and my secondary started dewing up completely. after a while the primary started dewing up as well.

just wanted to ask how do you'll overcome these issues?
I'm guessing secondary dew heaters are the way, but won't that distort images?
for the primary, they usually have fans to cool the mirror, but if it goes below dew point, do you'll use heaters/warm air?

I could use dew shields but if you're imaging over zenith, they won't be effective.
what is the norm with dew control on reflectors?

I did have a fan blowing air on the secondary and it helped a bit cause if I turned it off, it would dew up quickly, but with it on, it would take a bit longer.

Thanks
Alistair