dew prob.

lesbehrens (Les) · #1 27-12-2008, 01:32 PM

hi. i have a dew prob on my 2ndry mirror of my 16" truss dob. do u have any ideas on how to stop this.
les

JethroB76 (Jeff) · #2 27-12-2008, 04:35 PM

Depending on the design of your secondary holder you can fit an astrosystems secondary heater available locally from SDM

http://www.sdmtelescopes.com.au/shop...products_id=46

There area a few threads on IIS concerning the fitting of these to GSO/Lightbridge style scopes..

wavelandscott (Scott) · #3 27-12-2008, 05:19 PM

Secondary heater is a good idea...I've got one on mine and never have had a problem...

Do you have a shroud?
Fans on the primary?

lesbehrens (Les) · #4 27-12-2008, 05:45 PM

would a shroud help?
i didn't really want to put a heater on the 2ndry but if it has to come to that....
thanks
les

Davros (Lauren) · #5 27-12-2008, 06:59 PM

A shroud helped my 10 inch a lot. I used to dew up the secondary fairly easily but the shield i made up from a camping foam mattress stopped the problem on some sub zero nights.

lesbehrens (Les) · #6 28-12-2008, 12:10 PM

thanks thats good to know.
les

astronut (John) · #7 29-12-2008, 07:32 AM

Les,
I have a shroud and Dew/lightshield on my 12"Lightbridge.
These have worked very well, but under extreme conditions I've found the need for a secondary heater.
I use the Astrosysytems DG-1, (there is a thread on it in I.I.S)
It works brilliantly!!
Whilst others around are packing up or sitting it out because of the dew, I keep going all night!!
Worth it? Absolutely!!

lesbehrens (Les) · #8 29-12-2008, 09:31 AM

ok. cool. thanls for your help. ill give it a try.
les