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SCT 8'' Dew Shield

  • Jonathan King
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17 years 3 months ago #42647 by Jonathan King
SCT 8'' Dew Shield was created by Jonathan King
Hi,

I just picked up my new CPC 800 8'' SCT last week and am over the moon (!!) with how good it is. This is my first scope since childhood and god bless the SSIA...

I was wondering if anyone has made, brought or got any advice on what dew shield I should use.

I only found your site tonight, as I thought the AI site was the only one in the country.

Many thanks

Jonathan

Regards

Jonathan King

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17 years 3 months ago #42648 by voyager
Replied by voyager on topic Re: SCT 8'' Dew Shield
Welcome aboard!

Not sure if this is what you had in mind but I use a hair dryer. When the scope begins to gather dew just heat the corrector place gently with a hair dryer till it's fully clear, it will then stay clear for a good while. When it starts to fog up again, repeat!

Bart.

My Home Page - www.bartbusschots.ie

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  • DaveGrennan
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17 years 3 months ago #42650 by DaveGrennan
Replied by DaveGrennan on topic Re: SCT 8'' Dew Shield
Hi Jonathan and welcome to the boards.

I use a hair dryer on occassion too but as infrequently as possible. Its not ideal as it dries dust onto the optics and makes it stick. A better idea is to prevent if forming insofar as possible. You can make a dew shield quite easily using a large sheet of non absorbant material such as plastic.
Make a ring which fits snugly over your scope and protrudes about 8" above the optics. Dont make it too long as it will then act like a sail in the wind. If you dont fancy making one I don't think shop bought ones are too dear.

Best of luck with the new scope and don't be afraid to ask anything you're not sure of.

Regards and Clear Skies,

Dave.
J41 - Raheny Observatory.
www.webtreatz.com
Equipment List here

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17 years 3 months ago #42671 by Matthew C
Replied by Matthew C on topic Re: SCT 8'' Dew Shield
HI jonathan and welcome Aboards!

Ok 8" dew shields are widely available! Both flexible and solid dew shields but i dont think there is a specific one made for the CPC!

I presume the one for the LX meade series would fit!
www.greenwich-observatory.co.uk/acatalog/Dew_Shields.html

Welcome again!
Matthew

We shall not cease from exploration
And the end of all our exploring
Will be to arrive where we started
And know the place for the first time. . . .
T. S. Eliot
A wise man....

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17 years 3 months ago #42673 by Seanie_Morris
Replied by Seanie_Morris on topic Re: SCT 8'' Dew Shield
Dave Grennan's suggestion is probably the best Jonathan. You can even use those thin ground sheets you would use with your sleeping bag when camping. They fold up easily, cost less than €10, and will absorb moisture from the air around the scope aperture.

Welcome to the boards too! :)

Seanie.

Midlands Astronomy Club.
Radio Presenter (Midlands 103), Space Enthusiast, Astronomy Outreach Co-ordinator.
Former IFAS Chairperson and Secretary.

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17 years 3 months ago #42677 by dave_lillis
Replied by dave_lillis on topic Re: SCT 8'' Dew Shield
Hi and welcome.
I'm glad you found the site, why not tell your astro buddies about it :)
anyway, with an 8 inch SCT, a flexible dew shield can easily hold its shape, I've heard of people using underlay foam sheets, the type you'd put under a sleeping bag while camping, they are cheap and easy to use.
If you go down the road of a metal dew shield, be prepared for their weight, they can make the scope very front heavy, so you might need a counter weight system with it.
I tried making up dew shields for the 12" but found that they inevitably sagged at the top due to the big circumferance and lack of support, an 8 inch will have more success.
I bought a second hand metal dew shield on astromart.
www.astromart.com/classifieds/
I put up an add and got a perfect second hand meade metal 12" dew shield at a nicely reduced price. That site has saved me a fortune over the years.

You should also go down the road of a heater system such as the ones listed in the link.

www.kendrickastro.com/astro/dewremover.html

Kendrick make a heater belt that goes around the front of the scope by the corrector plate and keep the corrector slightly warmer then the air so preventing dew. A dew shield on its own is not a workable solution.
You'd also need to get their cheapest belt controller, its worth the effort.

The real trick with astro equipment is to shop around, you can save alot of money by doing a quick search in google..
Any other questions, just ask away.

Dave L. on facebook , See my images in flickr
Chairman. Shannonside Astronomy Club (Limerick)

Carrying around my 20" obsession is going to kill me,
but what a way to go. :)
+ 12"LX200, MK67, Meade2045, 4"refractor

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