SORRY - yet more dew heater questions!

[Andrew*]

I'm still in question mode I'm afraid. These ones aren't all simple either!

1. If I were to only use one of my two scopes at a time, would I need a seperate dew strip for each one?

Are there any issues with using a strip for an 8" scope on a 4" scope (other than using mroe power than necessary?)

2. How does newtonian dew prevention work? Do you need one strip for the secondary and another for the primary, or will one strip right on the end of the tube stop all dew from forming inside?

3. Ian King single channel versus Rigel dual channel Is the only difference that the output to 2 strips can be controlled independently from the other two?

4. Will 6amps be enough to run four strips at max power simultaneously?

5. Are there compatibility issues between different controllers and strips?

Thanks a lot all! You're all great!

Andrew

[Andrew*]

Sorry everyone - I must be trying to kid myself here. I'm still learning (boy, was that an understatement!!), so threads like this should really be in the learning zone. Could a kind mod please move it there?

Thanks

Andrew

[Kai]

I think this is in the right place Andrew.

[Andrew*]

if you say so.

[bern]

I'm still in question mode I'm afraid. These ones aren't all simple either!

1. If I were to only use one of my two scopes at a time, would I need a seperate dew strip for each one?

Are there any issues with using a strip for an 8" scope on a 4" scope (other than using mroe power than necessary?)

2. How does newtonian dew prevention work? Do you need one strip for the secondary and another for the primary, or will one strip right on the end of the tube stop all dew from forming inside?

3. Ian King single channel versus Rigel dual channel Is the only difference that the output to 2 strips can be controlled independently from the other two?

4. Will 6amps be enough to run four strips at max power simultaneously?

5. Are there compatibility issues between different controllers and strips?

Thanks a lot all! You're all great!

Andrew

Well let's start the ball rolling:

1, Ideally yes but you can use larger dew strips especially if they are of the frugal variety or well controlled. You'll get tube currents if there's too much heat delivered.

2, Many Newtonians don't suffer from dew, mine don't, but if they do then it's usually the secondary that suffers. They tend to need only minor amounts of heat to stay dew free, delivered to or very near the component(s) that has the problem.

3, Maybe, but there may also be a difference in how efficiently they deliver power to the strips.

4, Depends on the size and make of the strips but probably.

5, I have heard of some issues.

HTH

bern

[Andrew*]

Thanks a lot Bern for answering.

2, Many Newtonians don't suffer from dew, mine don't, but if they do then it's usually the secondary that suffers. They tend to need only minor amounts of heat to stay dew free, delivered to or very near the component(s) that has the problem.

Okay, I won't bother with an 8" strip then! I have had dew on my primary one bad night... almost literally!

I was wondering how you're meant get power to the secondary heater without having wires crossing your aperture that will affect contrast? Is it possible to get a battery powered secondary heater? Or what about conducting heat along the spider?

thanks again

Andrew

[James]

I believe you can either get a battery powered secondary heater that you'd need to mount on your secondary somehow or else traipse a wire along one of the spiders which shouldn't make a huge difference as the wire should be pretty thin...

... hoping a pro will come on and confirm this or otherwise... :?

I've never had dew on my primary but have had a fogged secondary many times. My way around that has been to use an Astrozap flexible dewshield on the front of the scope. Makes my scope look very long but has worked well so far!

James

[FLO]

A wire along one of the spider vanes would be fine Andrew.

I suggest you follow Maccers suggestion and try a dew-shield first as its the cheaper, simpler solution. First, wrap some black (preferably) card around the tube, extending it forward about 1.5x the tube diameter, and tape it there. If that fixes the dew problem then buy a proper dew shield. If not, you will need a secondary heater. HTH.

[Jaffa007]

Andrew,

This link should help: http://stargazerslounge.com/index.php/topic,2048.0.html

Just missing the pics, if Daz still has them?

This is my next project, ready for when I'm able to get outside again

James

[barkis]

And don't forget your eyepieces, if they are exposed to the cold night air, and you place one in your focuser, it will mist up as soon as you put your hot little eye to it. So, keep them warm too.

Ron.

[sublime_mick]

i keep my eyepieces warm in my pocket