Quote:
Originally Posted by Hemi
And the humidity makes transparency poor for at least half the year. I suspect humidity would be similar across the globe for similar latitudes.
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Strange. I have different experiences with poor transparency.
I've been to hot humid tropical climates several times (Bali several times, N Qld once, Tahiti, Fiji, Kenya east cost, KZN which is South Africa tropical east cost), but by far in most cases the sky was crystal clear when there were no clouds.
On the other hand, dry areas like N India and Dubai have an almost constant hazy sky due to blown up desert dust. When landing in Dubai, I see the brownish layer of dust as a blanket over the city.
In E China (and here in the EU as well with eastern winds) haze is caused by particulate matter pollution from mostly car traffic and coal fired power stations.
Water vapor is invisible, unless there are particles in the air which promote condensation. Even here in N Europe I have experience crystal clear nights when it was cold after showers from the northwest (clean N Atlantic ocean origin). The eyepiece / spider drum of my Dobson was quickly fogged due to moisture, but the sky was crystal clear.
And with temps barely above 0ºC the air can contain much less vapor than at 25ºC as in the tropics, where I don't have moisture problems, except at the beginning when I take out the cooler telescope from my air conditioned guesthouse room....
Anyway, DRW might have particulates and smoke from the Indonesian slash-and-burn of their tropical forests when the wind is west.