I am awaiting the arrival of my new 10 inch Sky-Watcher collapsible. I've been thinking about how much of a problem dew is and was looking at the Astrozap dew heater. However, I was wondering, you are instructed to allow your mirrors to have a cool-down period after setting it outside. Do these heaters effect the visual in a bad way. I realize that it won't effect the visual as much as a primary covered with dew. Any thoughts would be appreciated.
Posted 16 September 2020 - 06:59 PM
Provided you bought a shroud the Primary shouldn't be an issue for Dew however the Secondary will be. I went with a Secondary heater from R-Sky and it works great.
I don't start using it unless I see a little Dew forming on the Secondary.
- havasman likes this
Posted 16 September 2020 - 07:21 PM
Thanks Mike. I did purchase a shroud from Astrozap.
- havasman likes this
Posted 16 September 2020 - 07:25 PM
Secondary dew heaters do not cause heat distortion. Oh I guess they could if oversized and run wide open 100% of the time but that's not the drill. What I see that Astrozap offers is strips and controllers and I'm sure they work well. But I don't think they're what you need. You may be much better served by the Astrosystems Dewguard products that mount to the back of your secondary and incorporate not only the heater elements but sensors that read ambient temp and the mirror temp as well as a processor that switches the heater on & off to keep it at or just above ambient. All you add is power, either a 9v battery or wire it into your 12v system and you don't have to fret battery levels/spares. I have them on all my Dobs because I used to lose a lot of observing time to dewed up secondaries. Not any more. They're 100%. Talk with Randy if you need to check for application for your scope.
I also use the R-Sky products everywhere but on my secondaries and recommend them as high performance gear at reasonable cost. I didn't know they'd developed a secondary heater for stalk mounted mirrors. I'll bet it works. They're pretty constantly innovating new applications. Nice folks too. You will need a controller.
Edited by havasman, 16 September 2020 - 07:27 PM.
- stubeeef likes this
Posted 16 September 2020 - 07:30 PM
Thanks for the reply havasman.
Edited by Light Bender, 16 September 2020 - 07:43 PM.
Posted 17 September 2020 - 04:01 AM
I’m also a great fan of R-Sky dew heaters, but I use the Astrosystems secondary heater in my Dob. It has a built in thermometer and sets the secondary heat 1 or 2 degrees above ambient temp. All of the electronics are included on the heater board. You silicone the board to the back of your secondary, supply a 12 volt feed or plug a 9 volt battery into the connector and forget it. It does all the thinking for me. For an infamous airhead like me, that’s priceless.