Sky Clarity

[Tom Droege <tdroege2@earthlink.net>]

Arne and anyone else that wants to answer,

I am working on a "Sky Clarity" detector.  The idea is to measure the 
radiation loss to free space.  So far the device looks promising.

My idea is that for tass telescopes this might be a good way to select the 
best photometric nights.  Big telescopes would probably also want good 
"seeing", but I doubt that "seeing" makes much difference for tass 
measurements.  What I hope to measure is how much stuff is between the 
telescope and space.

I would like to put this measure in the .fits header.

Is there some "official" fits header term to use?

Tom Droege