[Paddy (Patrick)]

Hi All,

Many thanks for all of the valuable discussion in these forums. I'm new to astronomy - l I got started in February when my wife bought me a Tasco 114mm reflector. I got addicted pretty quickly and bought a bintel 302mm dobsonian about a month later and I think she might regret having got me started. No, she's very supportive really.

I have found a lot of the discussion about modifying these telescopes and also about EPs very helpful.

I am thinking about building a dew heater for the primary of my 12", especially after reading somewhere that dew and dust can damage the surface of the mirror. I've got some resistance wire, a 12v 7 amp/hour battery and a potentiometer and am thinking about fixing the wire to the back of the primary. I've sort of modelled the design and power requirements on the Kendrick units that I've seen advertised.

I wonder if people have found dew heaters necessary or desirable on primaries in big long newtonians and if what I have in mind is a good way to go about it.