THE WANDERING ASTRONOMER
Monday, October 2, 2023
The Other Eclipse
And the waiting continues.
The unbearably interminable interlude between the present moment and THE
event: a slow, but inexorable passage of the moon across the Sun on April
8, 2024. In 193 days (or 4639 hours), the Greater of all great American
eclipses - only two have been so designated*, including the one that has
not yet occurred- will commence. While our sinews assume a harp-string
tension, our respiration becomes increasingly more labored, our peripheral
neurons spark off like pyrotechnics and we realize that the mindfulness
tenant about living fully and exuberantly in every present moment while
paying scant attention to the future is little more than a heaping handful
of curdled codswallop, we shouldn't forget that another eclipse will occur
later this month!
*Saturday, October 14, 2023*
to be precise.
As is true with every eclipse, what an observer sees depends on the
observer's location. While those within the totality path will see an
annular solar eclipse, other less fortunate sky watchers will be treated
only to a partial eclipse, the magnitude of which decreases with increasing
distance from the totality path. As we can see from the map below, the
totality path begins in the north Pacific, slices across the western and
southern United States before meandering across the Gulf of Mexico before
gliding majestically over the Yucatan Peninsula , eastern Central and
finally across the northern part of South America.
[image: MZ-new-map-2023-annular.jpeg]
An annular solar eclipse occurs when the moon moves directly in front of
the Sun when it is at or near apogee, its point of greatest distance. As
the moon will be farther away than usual, its angular diameter (30' 5.8")
will be smaller than that of the Sun (32'04"). Consequently, the moon
will not obscure the entire solar disk. Instead, at 'totality,' the moon
will appear as a dark circle surrounded by a ring of fire, Mr. Cash.
The word 'annular eclipse' derives from the Latin word 'annulus' meaning
ring.
[image: xVN5pcgAtdxyKVFDt23qBn.jpg]
This gorgeous image shows the Sun during an annular solar eclipse. Image
credit: : Chayanan Phomsukwisit
Those outside the totality path will not see the ring effect. Instead, only
a partial eclipse will be visible. As one can readily infer, during this
type of eclipse the moon only blocks part of the Sun. And, one might ask,
"Well, isn't that true of the annular eclipse, as well?" To which we
reply, "This explains why lawyers should never write astronomy blogs."
We here in the Greater Portland area will only see a slightly partial
eclipse because we're quite a substantial distance from the Totality Path.
When the eclipse reaches maximum at 1:25 p.m. on Sat, Oct 14th, its
magnitude will only be 0.262. *Magnitude *refers to the percentage of
the Sun's diameter the moon blocks. This value is not the same as the
*obscuration* percentage, which measures the percentage of the Sun's
surface area the moon covers. At the magnitude of 0.262, about 17% of the
Sun's face will be shielded by the moon.
The Time-Table specific for Portland is as follows:
*12:21.00 p.m. Partial Eclipse begins*
We first see the dark edge of the moon against the Sun
*1:25.50 p.m. Maximum eclipse*
The time when the moon covers the maximum amount of the Sun from our
perspective
*2:30.16 p.m. Eclipse ends*
The moon is no longer seen against the Sun.
You can find the times relative to your location at the following web-site:
www.timeanddate.com/eclipse/solar/2023-october-14
While this event won't be dazzling enough to sow superstitious terror
amongst the intellectual elites, it does affirm the power inherent in that
hurly-burly witchery of mathematical astronomy: humanity's ability to
precisely predict the motions of grand celestial worlds. While we might
not exert any influence over the empyreal realm, we can at least know how
the celestial orbs interact.
Consider this a mere taste of the feast that awaits us in April.
*The first 'Great American Eclipse' occurred on August 21, 2017.
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