Dew control

[Rhino1980]

Just wanted to know, are the dew control bands that go on the outside of your tube effective on a Newtonian, or are they just for SCT's and Schmidt-Newtonians? Tried for first light tonight and got all of five minutes before she fogged up :doh:
Cheers

[JethroB76]

5 minutes? What was it that fogged up? The eyepiece?

If so, EP dew heater bands do a great job of keeping your EPs clear.

[AlexN]

Firstly, by dew control bands.. are you talking about a dew shield? or a heater band?

Also, which of your newt's mirrors is fogging? the primary or secondary?

For the secondary, a normal dew sheild should prevent dew for a certain amount of time depending on how damp the conditions are... you can buy secondary mirror heaters.. these are very effective...

Essentially, it should take some horrible conditions for dew to settle on your primary, as the long tube should act as a dew sheild... however a heater band wrapped around the tube right over where the primary mirror is housed should stave it off should that be fogging up...

The down side to heaters is that there will then be thermal currents inside your tube that will appear much like poor seeing through the eyepiece or camera...

[Rhino1980]

Hey guys thanks for the replies. The Primary fogged up something fierce. As did the finder scope etc. It's colder than a witches booby but I can't recall ever having my last scope fog up so quick and I've had that out in the cold too. I was thinking of the heated bands with the controller. Considering Alex's advice, maybe one up near the top to keep the secondary and EP's good and one down the bottom for the primary would work? And by having the controller I should be able to minimise currents?

[astronut]

Ryan,
Does your primary have a fan?
If not, install one, they are very effective at keeping the dew off the primary.:thumbsup:

[Batfink]

Hi Rhino,
Maybe you should move down here to Newcastle, I had a great couple of hours viewing, till the clouds came, with no dew problems at all.

Peter

[Rhino1980]

Hi guys, thanks for the responses. I will do some research into a 12 Volt fan for the primary, should be an easy mod. :thumbsup: Might try that before going to heaters too.
Thanks for taking the time to help :hi:

[Starkler]

Weird, I have never had a primary mirror fog up on me. I would have assumed you moved your scope from somewhere cold to a warmer place for that to happen.

A fan is the go. You definitely dont want to be artificially heating your primary mirror.

[Rhino1980]

Thanks mate. I have never had it happen to my smaller 130mm scope.