Hi John and others in the golden west,

You make the case that the sun truly sets earlier than it appears to do.
If, as you say, 34 minutes of arc represents 2.26 minutes of delayed
sunset time due to refraction, we are getting into seconds.  In that
case we must do what the Nautical Almanac does not, and consider the
height of the observer's eye.

The late Mr. E.W. Barlow, a meteorologist in the British Met. Office
once told me that while serving aboard one of the ocean weather ships he
saw the green flash (visible under very clear conditions at the moment
of sunset) three times at a single setting.  This he said he achieved by
moving to successively higher decks as the sun went down.

Pondering this, I have reckoned that if the decks were, say, ten feet
apart he would have about four seconds to move from one deck to the
next.  I wonder if, being prepared, such a feat would be possible and
whether anyone else has ever attempted it.  Or was he just hauling my
leg?
Frank


-- 
Frank Evans

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