Anybody tried dew heater on secondary mirror?

[emadmoussa]

Last night was a reminder why I loved refractor...they're simply dew fighters...first light with my GSO 10" Dob, Telrad, finderscope and secondary mirror all got fogged up after 1  hour. I was expecting that for the Telrad, but couldn't bother fixing it up since I was outside just testing. But the secondary mirror which is slightly on the inside of the tube got foggy faster than I expected. How do you go about attaching a dew heater to it? Won't that add extra light obstruction? Or shall I just settle with a homemade - and usually ugly - dew shield?

[Pig]

A heated dew shield works brilliant Imad

I was out for 5 hours the other night and even the huge corrector plate on the SCT was clear the whole time.

[leelee970]

On my 10" Dob I use a home made dew shield - no problems with fogging up.

You could use a 12V hairdryer.

Or you could make (and I believe buy) a secondary dew heater pad - you'd need a dew controller as well.

I made both for my Obsy fixed reflector. There are many sites showing you how to make one.

[Pig]

I didn't bother with a controller in the end I just leave it on full

[emadmoussa]

On my 10" Dob I use a home made dew shield - no problems with fogging up.

You could use a 12V hairdryer.

Or you could make (and I believe buy) a secondary dew heater pad - you'd need a dew controller as well.

I made both for my Obsy fixed reflector. There are many sites showing you how to make one.

I can actually make the dew shield very well...I was just wondering in terms of dew heater being list intrusive and lighter. Well, I guess dew shield will be the way to go..

[crashtestdummy]

I recently made a dew heater set up for my 16" dob as a dewshield ontop of a 6' high scope is too much.I have heaters on the secondary,both ends if the finderscope and one for the eyepiece.I have two lighter sockets connected to a sealed lead acid battery and a portable hairdryer too as due to the aperture size of my scope you get dew down the tube onto the primary when observing at above about 60° altitude.

[Oily]

I made this dew heater for my secondary,made no difference to light intrusion

[m.tweedy]

Altair sell them

http://www.altairastro.com/product.php?productid=16480&cat=243&page=1

http://www.altairastro.com/product.php?productid=16275&cat=243&page=1

http://www.altairastro.com/product.php?productid=16276&cat=243&page=1