dewshields for Binoculars

Thats neat, Mike. I would have never thought trigonometry could be useful to a simple pair of binoculars like this!

Its pretty cool alright. With Dew shields of 10 cm for my 20X80's I will need them to have a diameter of 87mm minimum. As the casing for binocs is 100mm in diameter I can build them flush with the binoculars which should make things easier, and means I will be able to observe for longer.

Out of curiosity Trevor, what are using for the shields?

Dont know yet. There is some black drain pipe out the back which I think from rough measurements is the correct size to slip over the binoculars. If that does not fit then I dont know. I have to do something though, I have been dewed over on a few occassions and last saturday night I was dewed over within an hour or two.

I always wondered about recycled cardboard/heavy paper. It is quire absorbant to take in the moisture in the air around the bino objectives. Being small lenses (like eyepieces) they do tend to dew up faster than larger aperture optics.

Dont know yet. There is some black drain pipe out the back which I think from rough measurements is the correct size to slip over the binoculars. If that does not fit then I dont know. I have to do something though, I have been dewed over on a few occassions and last saturday night I was dewed over within an hour or two.

Trevor - if you are going to Galway, I have some off-cuts of ProtoStar flocking material you can have. It is synthetic and high-tack and if the pipe is not matt, it'll make a difference. Some say flocking also helps delay the onset of dew.

Before anyone else asks, the offcuts wouldn't flock anything more than a 3" reflector. Sorry...

Dave