Dew Shields?

[Dave1]

Hello everyone,

I need to get a dew shield for my Skywatcher Skymax 180. From what I've read here, its advisable to get a dew heater strip, or I was thinking of the Astrozap Flexi-Heat Dew Shield. I really up until now have kept away from any thing that is electric. I don't use a phone, computer, or any battery device when I observe. I like to keep it clutter free, and use planisphere and star charts. 

So I don't know the math to figure this out. What is the smallest 12v battery I can use to power a dew heater strip ( smallest amount of amps )? 

Dave

 

[nightfisher]

Just a suggestion....make a dew shield out of cheap materials and see how much improvement before going dew heater, i never use a heater with Maksutovs 

[Paz]

22 minutes ago, nightfisher said:

Just a suggestion....make a dew shield out of cheap materials and see how much improvement before going dew heater, i never use a heater with Maksutovs 

I would agree with this. I've got a home made dew shield for my maksutov and no heater. Often I don't even use the dew shield if conditions don't require one as my observing sessions are usually short stints.

[Dave In Vermont]

It really is dependent on your particular weather-conditions where you observe from. Many folks in the UK have terrible dew and foggy conditions a dew-heater strip would me an immense improvment, where as not so elsewhere. Same over here - some where you need windshield-wipers! Myself - never needed such. Just an Astrozap dew-shield. Or two - SCT & Mak are among my instruments (aka: Time-Machines)

So I concur with Jules: Make a dew-shield if you can, and see it that alone won't be sufficient.

Enjoy! The sky is free!

Dave

[N3ptune]

I like the heater straps during winter only at -10 celcius to keep the optic warmer outside, I get a bit of turbulence but the main purpose is to make it much easier to take the telescope back inside inside the house at the end of the observation, (preventing water formation on the mirror surfaces)

Otherwise I don't really use the heaters. With a refractor or a mak, I would also use a dew shield.

[Dave1]

Thanks for the suggestion guys. I sort of made a home made dew shield from a camping mat. Not a very good one mind, its not round. I have tried to make it round using tape in strategic places. Worried about vignetting. Will see what happens.

If I buy an electronic dew shield it will be one of the Astrozap, where it has the electronic heater built in, so that if I do need to use electricity the option is there. It works out better than buying both separately. I managed searching online to find the maths I needed to figure out what battery I would need. I'll probably get Li-ion Battery 12v, 7 amps. With a Dew Buster Controller. Hopefully this wont be needed thought.

Dave

 

[cjdawson]

Don't worry about Vignetting. The shield should help to cut down on some stray light that's entering the scope.  My first dew shield was made from a camping mat, it worked well, and was enough to see how much improvement there was.