Quote:
Originally Posted by avandonk
Optics get below the dew point by radiative cooling. That is they lose heat by radiation to a sky which has a temperature of 3 degrees Kelvin. All the dew shield does is limit the amount of sky the optic can 'see'. By very gently heating the dew shield it will then radiate to the optic so counterbalancing the heat loss to the sky. The last thing you want is heat to conduct to your optic. This will distort its figure.
With that out of the way very nice telescope. It does not get much better than this at this aperture. I am sure your joy with its use will be greater than my/our envy.
Bert
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I believe it's a very good idea to keep fluorite optics dry as they are susceptable to pitting if wet, the CaF2 is slightly soluble in water.
Probably a good idea to use the demister.
molar soubility is 1.24 x 10^-3 at 35deg C.
Ksp = [Ca2+] [F-]^2
= x ( 2x)^2
= 4x^3
= 4 ( 1.24 x 10^-3)^3
= 8 x 10 ^-9