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Dew shield for a dob

Astronut

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Astronut

Astronut

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I'm after a dew shield for my dob before I venture out to another SP. After seeing one actually working on Mel's 'scope this weekend it's been proved to me that they really do keep dew on the secondary at bay. I'm reluctant to get a heating solution as this would involve getting a power pack too.

I've been looking at the Astrozap shields on FLO but they seem to be aimed at refractors and SCT's. Would an appropriate sized SCT one fit my 12" dob? Any recommendations?

The outside diameter of the tube is 14".

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Astro_Baby

Astro_Baby

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Ooops I miseld you as well there hon - I think I said mine only cost a few quid. It did but I forgot I got it in a swap with someone I work with. She bought it for her SCT and then never used it so sold it to me cheap in a swap.

Also I know your power averse ( and to me thats sensible ) but Kendrick do a wrap around dew heater for a a newts secondary mirror. Its £35 though and you'd need a Kendrick controller to drive it. The part code is 2028.

By the way my dewshield was marked as being for an 8" SCT. It was from Orion but the sticky tag has fallen off mine with the part code info on it.

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FLO

FLO

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After seeing one actually working on Mel's 'scope this weekend it's been proved to me that they really do keep dew on the secondary at bay.

Yes, they certainly do work :)

I'm reluctant to get a heating solution as this would involve getting a power pack too.

A heated dew shield wouldn't be effective on a Newtonian/Dobsonian

I've been looking at the Astrozap shields on FLO but they seem to be aimed at refractors and SCT's. Would an appropriate sized SCT one fit my 12" dob? Any recommendations?

Just order for the same aperture-size SCT

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GazOC

GazOC

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This may get complicated but....AstroNut said he didn't want to powered solution (you quoted him), you replied that a heated dew shield wouldn't work on a Newt. I think that AstroNut just meant heating the secondary rather than a heated dew shield....PHEW! :)

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FLO

FLO

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This may get complicated but....AstroNut said he didn't want to powered solution (you quoted him), you replied that a heated dew shield wouldn't work on a Newt. I think that AstroNut just meant heating the secondary rather than a heated dew shield....PHEW! :)

Aaaaaaah ..... ok :(

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Astronut

Astronut

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Sorry if I caused some confusion re. heated solutions. I'd rather not have to resort to relying on power if possible and although a DIY solution will cost next to nothing I really couldn't be bothered sourcing suitable materials (mat, glue, velcro, etc). Besides, I don't mind spending on upgrades as I've spent a small fortune already (especially on eyepieces :clouds2: ) and a few extra quid won't go amiss.

One of those Astrozap shields will do me. I'll ring you later, Steve :)

It'll double as a light shield too which is an added bonus.

Thanks guys and gals.

Ian

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Sam

Sam

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Don't worry, you didn't miss much the secondary dewed very quickly - though it was spectacular before that - had a good very of Little Dumbbell, M31,32 and M110, also got M33 and loads of Milky Way surfing. :clouds2:

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Astronut

Astronut

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I caught M33 in the 10x50 binoculars later on - it was very easy to spot which shows how dark the site was - not possible from my back yard.

The highlight for me was the eastern veil nebula and the witch's broom (west veil) with the UHC filter and the XW30 - without the filter they were almost impossible to see :clouds2:

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Astro_Baby

Astro_Baby

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I think I was the only one not affected by dew too badly. My finderscope caught it bad on the second night but that was me getting smug and leaving the covers off the finder :clouds2:

Okies - it did get confusing there. I used just a basic dewshield - mine cost a few quid in a swap with someone I work with. To be honest I never realised they cost much more and having had a look I think I got a real deal there.

I only mentioned the Kendrick secondary mirror heater solution as another option. Its like a little blanket that wraps around the secondaries holder. To me it seems a bit complex as you need a controller and power and also ugly as you have to run wires along the spider vanes but it is an option and people with a bump for technology might prefer it.

I found the basic dewshield worked very well both nights when everyone else was struggling - I also had a cheap 12v haordryer to run off my power pack which only got used once by me to knock the dew off the finderscope.

To be honest - given the aggro other people seemed to be having with secondaries dewing up I would have said whatever a dewshield costs it would be worth it. The dew was amazing - I dont think I ever saw dew forming on stuff almost as soon as the sun went down. By the time it was truly dark my scopes tube was aboslutely running with water.

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timetraveller

timetraveller

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Ill second that thought sam / ian and co im definatley going to get one i had the shock of my life when i got up the following morning and checked my scope my primary was totaly streaked luckily with a little time in the breeze the mirror had completely dried off and went back to its new pristien condition without leaving a mark. im thinking im a lucky puppy in getting away spot free so to speak but i have learned a valuable lesson here regards Pete

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dogfish

dogfish

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I think I was the only one not affected by dew too badly.

And the SCT owner who's had lots of prior battles with dew and who brought along a dew heater system :mrgreen: although I quickly thought about getting some 1.25" tapes as my EP's dewed up pretty badly.

Martin

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