THE SOUTHWORTH PLANETARIUM
70 Falmouth Street      Portland, Maine 04103
(207) 780-4249      usm.maine.edu/planet
43.6667° N    70.2667° W  Altitude:  10 feet below sea level Founded
January 1970
2021-2022: XCIII
"Stonehenge might lose a bit of its allure if archaeologists ever unearth
croquet mallets."
-Anonymous

THE DAILY ASTRONOMER
Tuesday, March 15, 2022
In Exactly Two Months...

we'll experience a total lunar eclipse, provided, of course, the weather
cooperates. And, honestly, this is New England, when has it not? A while
ago we devoted a couple articles about this impending eclipse and now that
we're merely two months shy of this spectacular event, we wanted to send a
reminder that on May 15th/16th, the full moon will glide through Earth's
inner shadow like an oil-coated seal down the Kilimanjaro Water Slide in
Brazil, sans the splash and screams, naturally. Also, we wanted the most
recent subscribers to be made aware of this eclipse and information
pertaining to it.
We re-post the time-line:


*May 15 - 9:32 p.m. PENUMBRAL ECLIPSE BEGINS*
Earth's shadow is divided into two regions: the light, outer part
of Earth's shadow, called the 'penumbra,' and the inner region called
the 'umbra.' The penumbral eclipse begins when Earth first touches
the penumbra. The moon passes completely into the penumbra before it
reaches the umbra. Honestly, unless you're one of those mystical poetic
types who can actually tell the difference between a whisper of a breeze
and a caressing zephyr, you won't notice much during the penumbral part of
a lunar eclipse. Perhaps the brilliant moon's pallor is rendered a
few phantoms less vibrant, but even that is a stretch.

*May 15    -    10:27 p.m. PARTIAL ECLIPSE BEGINS*
This is when the 'action' starts. The umbra is the dark interior shadow.
Once the umbral eclipse begins, we'll see Earth's curved shadow against the
moon. We'll watch the shadow migrate across the moon until the moon is
completely immersed in Earth's shadow.

*May 15    -    11:29 p.m. TOTALITY BEGINS*
Totality begins when the moon is completed inside Earth's umbra. The moon
will not be wholly lost from sight. Instead it will appear reddish, because
Earth's atmosphere scatters blue light, but directs red light into its
shadow. (We see a blue sky during the sky because of this effect.) The
eclipsed moon will reflect this reddish light back to us, producing the
ominously named 'blood' moon. One effect that we think is absolutely
magnificent is the 'spherical moon' phenomenon. During totality, the color
differential across the moon's facade lends it a spherical appearance. The
moon actually appears as a crimson sphere in space, as opposed to the full
moon's usual disc-like appearance.

*May 16    -    12:11 a.m.   MAXIMUM ECLIPSE*
When the distance separating the center of the shadow and the moon's center
is at a minimum.

*May 16   -   12:53 a.m.       TOTALITY ENDS*
At this moment, the moon starts its exit from the umbra.  We will see a
thin sliver of the moon emerging from the inner shadow.

*May 16  -    1:55 a.m.    UMBRAL ECLIPSE ENDS*
For all intents and purposes, the show is now over.  The moon completely
leaves the umbra and appears, well, like a full moon again, except that it
remains immersed in the penumbra.

*May 16 -    2:50 a.m.    PENUMBRAL ECLIPSE ENDS*
The eclipse event is now technically over.  Of course, the moon's
brightness is hardly diminished during this last hour because the penumbra
is so faint.

Weather permitting, the Southworth Planetarium will be open for the
eclipse. We'll offer a brief presentation around 10:00 p.m. in our star
dome theatre before venturing outside to observe the event. Our intention
is to remain until 1:00 a.m. Experience teaches us that interest wanes
-i.e. plummets- once the moon begins to leave the umbra. We never charge
admission for the observation of celestial events. Being congenial sorts,
we always accept donations, but we won't solicit them that evening.

We do recommend making reservations, however. To do so, please send a reply
or call 207-780-4249.


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