A question about Dew Control

[Bladerunner]

Hi all,

I'm still a newbie without a scope but that should be coming in a couple of weeks...pace....pace. While I am waiting I have been trying to think ahead and make plans for the additional 'bits and bobs' that I will need.

One of these is dew control. My own research is leading me towards getting a HitecAstro 4 channel dew controller and 4 dew strips to deal with the scope's objective lens and eyepiece as well as the finderscope's objective and eyepiece.

I will be using a 2 " star diagonal and wonder whether it is possible to heat the rim of the diagonal holding the eyepiece rather than the eyepiece itself. I anticipate I would have to use a longer dew strip, say a 3" rather than a 2" strip, to compensate for the increased thickness of the diagonal. My thinking behind this is that I could keep alternative eyepieces in a pocket and if I then wanted to change eyepieces I would not have to unattach and re-attach the dew strip (which might be fiddly with cold fingers!).

My question is would the dew strip provide enough heat to the diagonal to keep the eyepiece dew-free?

Your thoughts/experience would be much appreciated

Best wishes

Geoff

[brantuk]

So long as you've allways got an eyepiece in the diagonal I've allways found it enough just to put a band round the eyepiece. Never had any trouble with the diagonal. If the dew gets so bad that the diagonal is affected, then it's probably time to pack up anyway

[Syzygy2011]

Hi Bladerunner!

I made my own heater control and 2 X dew heaters. Total cost was about £20. If you look at the links it explains all. You don't have to be technically minded, but if you want some help if you decide to go this way... let me know!

For the heater strips.

Build a Dew Heater from Resistors - IceInSpace

For the controller....

Building a Pulse Width Modulated Dew Heater Controller - IceInSpace

Good Luck!

Syzygy...

[Bladerunner]

Hi guys,

Thanks for the replies.

Brantuk, I think I may have confused the issue but couldn't think how to word it. I wasn't meaning to intentionally heat the diagonal mirror itself, only the (round) end that holds the eyepiece (can I call it the collar?). I was seeking to find out if it is possible to avoid having to take off and re-attach the dew strip each time I change eyepieces by heating the end of the diagonal instead, hoping that there might be sufficient heat in the collar of the diagonal to also heat the eyepiece. Does that make sense? Thanks for taking the time to reply.

Best wishes

Geoff