Dew Shields.....How Big?

[king-jaffethehutt]

Just made some homemade dew shields. what length should they overhang the scope by?

Cheers

Scott

[Merlin66]

For a refractor x1.5 to x2 the aperture.

[RikM]

For my 150 and 250mm Newts, the dewshields are both 300mm long and slide onto the tubes far enough to rest on the spider adjusters.

[king-jaffethehutt]

Thanks guys.

down to the spider and around 13" overhang on my Newt, will trim a couple of inches of it.

Mak is a lot easier as can slide that one up and down the tube, can vary that one from 7.5" to 11" so that one will be okay.

Thanks again

Scott

[brantuk]

Don't cut off too much because they not only help to keep the secondary dew free but also help to block out stray light, giving crisper more contrasty views. Try it full length first - you can slide it up and down the tube to find the best position - then trim what's not needed

[king-jaffethehutt]

Not cut it yet Brant, think I will field test it first...but not tonight as it's chucking it down in the very aptly titled "Rainy Manchester":(

[brantuk]

Yeah - wall to wall clouds here too and a bit of mist

[nightfisher]

dew shield on my 180 mak is about the length of the ota itself and works a treat, like brantuk says, it blocks stray light, are you flocking the inside of the dew shield, it helps, here is a pic of mine

[king-jaffethehutt]

No, but I must admit to thinking about it. must admit it was not for the light though.

I was thinking about with the inside of the dew shield being very smooth and the condensation running into the scope. was thinking of black toweling but flocking should do the trick too!

scott

[andyboy1970]

I just made some for my scopes out of camping mat and they are all 2 foot long and work a treat.

[king-jaffethehutt]

Fair do's they are Big un's !!