help=dew

[sam mayo]

i am making a dew shield but i was told that only prolongs not stops dew,i was looking at dew strips heater would love advice on what u do and whats best i have a dob ssw 250px many thanks sam

[Lenny147]

Camping mat which only costs around £5 and is easy to cut to size, hope this helps

[crashtestdummy]

does your tube have a fan at the bottom sam?

[valleyman]

I use neoprine same stuff as for wet suits.

Just cut it to the diameter size, and make sure you make it at least 15" long.

I stitched the seams and it works fine

[x6gas]

The only way to completely avoid dew is to keep the temperature of the optics above the dew point and that means a dew heater, probably.

But a dew shield on a Newtonian (not massively prone to dew anyway) is probably all you'll need. If you are suffering from dew, worth determining whether it's the primary or secondary mirror going first. I use a camping mat on my HD11 cat - Stanley knife, velcro and a hot glue gun and jobs a good 'un (but that is supplemented with a dew heater too).

[James]

Just use a roll of camping mat for the front of the scope. This should delay the onset of dew considerably and will probably give you several hours trouble free viewing. Keeping the cap on the front can help too if you disappear inside for a cuppa! If things are really severe then a dew heater for the secondary may be necessary but ever since putting a dew shield on the front of my 10" Newt I've only had one night where the dew got me (one of the Kelling autumn star parties... everything was swimming in dew within an hour of darkness).

James

[stickbow]

Hi There

This is what I made and it cost about £5-00 I also made a small one for the telrad finder and they both work great for many hours.

http://stargazerslounge.com/topic/148996-home-made-dew-shield/page__hl__+dew%20+shield#entry1545621

[Mike73]

Depends what you want to keep dew off Sam.

If its just for your secondary then as others have said a camping matt will be fine.

My new scope I have on order has secondary heater and also fans on the primary so I'm going to use a Telrad heater since I will have a power supply for the fans anyway.