THE SOUTHWORTH PLANETARIUM 207-780-4249   www.usm.maine.edu/planet
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70 Falmouth Street   Portland, Maine 04103 43.6667° N
 70.2667° W  Altitude:  10 feet below sea level Founded January 1970 Julian
Date:  2459319.18
2020-2021: CXII

THE DAILY ASTRONOMER
Thursday, April 15, 2021
Exploratorium XLII:  Solar Eclipse Questions

Heavens above!
We certainly aren't the only ones giddy with glee over the 2024 solar
eclipse. Yesterday's article elicited quite a few responses and, naturally,
questions. Although we've been a bit question-happy this week, we decided
to address this latest batch of queries straight away.  After all, the
April 8, 2024 solar eclipse is now just 1094 days away: a veritable
eye-blink by cosmic standards.

*Because of the Saros cycle, if we miss the 2024 eclipse, will we only have
to wait 18 years to see the next one here?  -L.W.*
Excellent question!
First, we'll explain that successive eclipses within a given Saros Cycle
are separated by 18 years, 11 days and 8 hours.   The next Saros 139 solar
eclipse following the April 8, 2024 event will occur on April 20, 2042.
However, because of that "8 hours," that eclipse will be located 1/3 the
way around the globe:

                    [image: SE2042Apr20T.png]
The eclipse on 20 April, 2042, the next Saros 139 solar eclipse following
the 8 April 2024 event, will be an Asian/Australian event.

The next Saros 139 solar eclipse occurs on April 30, 2060 and will be
visible in parts of Africa, Europe and western Asia.      The following
Saros 139 event will happen on May 11, 2078.  As we can see from the
graphic below, that one will also be visible in North America:


                 [image: SE2078May11T.png]

Although the totality path will be different from that of the April 8, 2024
eclipse, the May 11, 2078 event will be the next Saros solar eclipse
visible in North America.         The period of three Saros Cycles is
called an *Exeligmos.  *Successive saros eclipses that are visible in the
same region of the world are separated by one exeligmos, a period equalling
54 years and 33 days.

*Will I need eye protection to watch the total solar eclipse?*
*-J.L. *
Yes.  You will need eye protection to watch the eclipse's progress.
 However, you won't need protection to view the eclipse during totality.
HOWEVER, if you are observing the Sun during a total eclipse without eye
protection, be SURE to look away just before totality ends.    If you
don't, you will be looking directly at a sliver of sunlight which could
prove injurious.     For this reason, when you do observe the eclipse, be
certain that you know the precise timing, which will vary from location to
location.

*Will the stars be visible during the total solar eclipse?*
*-Jack. H*
Yes, they will.     One will see the stars and nearby planets during
totality.   During the April 8, 2024 eclipse, the Sun will be in the
constellation Pisces the fish.
During the eclipse one will see the planets   Mercury (very faint), Venus,
Mars and Jupiter.        Saturn will have already set by the time totality
begins.

[image: ezgifcom-resize_13.jpg]
Sir Arthur Eddington led an expedition to observe the sky during a total
solar eclipse in 1919.  He was able to photograph the stars surrounding the
eclipsed Sun and from the positions of the stars verified that starlight
was affected by the Sun's gravitational field.  This observation provided
the first piece of corroborating evidence of support of Einstein's General
Theory of Relativity.

*Will you be holding a special event at the planetarium?*
*-J.O .  *
We will certainly have a special event, but we will be traveling up to the
north or west so as to be within the totality path.   Unfortunately, this
eclipse will not be total in Portland.  Our hope is to be where the action
is.       That brings us neatly to the last question.


*Any idea what the weather will be like?  April in Maine tends to be a bit
inclement.*
*-S.L.*
No idea. Astronomers can predict planet positions with certainty over
centuries.  Meteorologists deal with far more elements and so their
predictive powers are limited.    Yes, April in Maine tends to be very
unsettled.      Unfortunately, there is no way we can know the weather
until just before the eclipse.


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