On Mon, 07 Jan 2008 01:10:58 GMT, John Schutkeker
jschutkeker@sbcglobal.net.nospam> wrote:
When the weather section of my daily newspaper specifies that sunset
or sunrise are at particular times, is that the time that the midline
of the sun crosses the horizon, or is it the leading or trailing tip
of the sun?
Rise, Set: During the course of a day the Earth rotates once on its
axis causing the phenomena of rising and setting. All celestial
bodies, stars and planets included, seem to appear in the sky at the
horizon to the East of any particular place, then to cross the sky and
again disappear at the horizon to the West. The most noticeable of
these events, and the most significant in regard to ordinary affairs,
are the rising and setting of the Sun and Moon. Because the Sun and
Moon appear as circular disks and not as points of light, a definition
of rise or set must be very specific, for not all of either body is
seen to rise or set at once.
Sunrise and sunset conventionally refer to the times when the
upper edge of the disk of the Sun is on the horizon, considered
unobstructed relative to the location of interest. Atmospheric
conditions are assumed to be average, and the location is in a level
region on the Earth's surface.
compare the times with what you can get from this site:
http://aa.usno.navy.mil/data/
