"John Ladasky" wrote in message
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"George Dishman" wrote in message
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"Eugene Shubert" wrote in
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"Mr. 4X" wrote in message
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(Eugene Shubert) wrote in
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om:
What is the darkest hour of the night?
That depends on a lot of things. There is almost no direct sunlight
2-3
hours after sunset,
Isn't there a measurable amount of sunlight that's scattered by the
atmosphere, reaching further into the night than a mere 2-3 hours of
earth rotation?
Zodiacal light.
I thought that the zodiacal light was scattered off of Solar System
dust in the plane of the ecliptic, rather than Earth's atmosphere?
Yes, I was unclear. When Eugene said "Isn't there a
measurable amount of sunlight that's scattered ..."
I wondered if he was recalling discussion of the
Zodiacal light rather than atmospheris scatter.
I was too economical with my words (most unusual).
It will be darkest at local midnight in midwinter
when the Moon is new and Venus is below the horizon.
I wonder how often that combination occurs (if ever).
How can Venus *not* be below the horizon at local midnight? Venus
reaches a maximum elongation of about 48 degrees relative to the Sun.
If I've done the math correctly, Venus should always be below the
horizon by 3 hours and 12 minutes after sunset.
Again I stand corrected. It should have been obvious
to me since Venus is inside our orbit. Thanks for
picking me up on those.
best regards
George