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What do I need for winter viewing w my lightbridge

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#1 Blakheaven

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Posted 20 October 2013 - 12:40 AM

Hello all,
I have a new 12" lightbridge and it is my first truss tube scope. I have a light shroud, but I am having trouble finding a dew/light shield for the secondary. I assume the 12" astrozap wont fit as its for an SCT. Is it common for LB owners to go with the 14" sct design to fit the 12" LB?
As for electric dew zappers I should get an eyepiece heater but should I get two bands? One for the upper assembly and one for the lower? And again what size should I go with as they don't advertise for lightbridge/truss tube designs.
Thanks for any help
Jake C.

#2 acochran

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Posted 20 October 2013 - 02:06 AM

Astrozap makes something called a light shield for Lightbridges, but it's not for dew, just to help with street light, etc.-does not go all the way around the tube.
You might need a heater for the secondary mirror. Blowing on the secondary mirror with a hair dryer also works, temporarily.
Andy

#3 JimMo

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Posted 20 October 2013 - 12:38 PM

Hi Jake,

Dew straps will do nothing wrapped around the upper tube assembly. A good shroud will help keep the secondary dew free except under the worst conditions. IIRC the Lightbridge has a glued on secondary so this one from Kendricks will work for that.

For eyepieces I don't usually bother with a strap unless I'm using one exclusively. When I change EPs I cap them and put them back in my case that's protected under am minivan's hatchback. I do like to keep the telrad clear as I have a heater for that and my 60mm finderscope. All this is controlled by a Thousand Oaks Dew controller.

#4 JimMo

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Posted 20 October 2013 - 12:39 PM

Oh, and a good pair of insulated boots. :grin:

#5 kevint1

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Posted 20 October 2013 - 01:31 PM

You need clear skies and warm clothes... Warm boots, gloves and something on your head. The winter skies are fantastic, if you're prepared.

#6 Blakheaven

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Posted 20 October 2013 - 02:25 PM

Thanks for the feedback and I am well off in the clothing department haha.
I see some dew shields have heat strips built in them. That and all the dew shields (I have seen the astro zap light shield, but that looks worthless for my area)
Would a 14" sct dew/light shield fit a lightbridge 12"? And would 14" act straps work for the primary?
Excuse me if I am being redundant.

#7 Astrojensen

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Posted 20 October 2013 - 02:58 PM

Based on my experiences with my own 12" LB, you won't need to worry about dew on the primary mirror. I don't think I can recall a single time it has dewed up. The secondary, however, is a dew magnet. I use a hairdryer to keep dew at bay, plus the shroud, of course. You don't want a SCT dewshield with heat strips, since the heat will be so far away from the secondary, it'll be useless and only create thermal turbulence. A small heater strip on the back of the secondary is what you want. Or a hairdryer, as mentioned. A hairdryer will also keep your hands, Telrad, finderscope and eyepieces warm.


Clear skies!
Thomas, Denmark

#8 JimMo

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Posted 20 October 2013 - 08:08 PM

A small heater strip on the back of the secondary is what you want.


Yes, like I linked to above. There are others but that one works with a glued on secondary.

#9 Blakheaven

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Posted 27 October 2013 - 01:27 PM

I actually ended up emailing astro zap to inquire if the 14" sct dew shield would work. Ended up they are making me a custom dew shield for the LB for a reasonable cost of 65$+shipping.

#10 Starman1

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Posted 27 October 2013 - 08:03 PM

That should work. With the dewshield, the secondary will be buried far enough into the tube to make dew unlikely.






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