Quote:
Originally Posted by Shiraz
I also get better results with wind - seems to break up the turbulent columns of air that (I assume) develop if it is still.
It was still here, but after a sunny day, this site gives poor results in still air. I put that down to thermal columns developing over the roadways and houses in the town, but that is no more than a hunch. With onshore sea breezes, everything cleans up and seeing can get below 2 arcsec. But sea breezes around here can be 20+ knots, which brings another set of problems.
|
Hmmm interesting. At Clayton typically there is wind all day ranging from a breeze to gusts. Always coming from the southern ocean (ocean being heated). Once night falls the heating stops and winds cease. It is rare to have wind at the site at all over night. We mainly get them in summer when the high pressures are over NSW or just leaving the NSW coast. I am sure the presence of Lake Alexandrina close by also influences the conditions there too. There is no topographic features for 30km or more in any direction. If there is wind at Clayton the seeing is not at good for me. The heated air is more turbulent and it is coming from over the Mt Lofty Ranges 35km away. Far enough away to settle a bit but still enough to make the seeing degrade a bit.