[image: cropped-lotus-eaters1.png]
*The Lotus-Eaters:*   The first food addicts
Odysseus and his men faced many dangers during their arduous voyage from
Troy back to Ithaca.  In fact,  the odyssey was so perilous that only
Odysseus survived it.   For instance, they encountered the dreadful cyclops
Polyphemus who ate a few of Odysseus' crew before he and the other
survivors escaped.  They also came to cross-purposes with Circe, the witch
who transformed some of the men into swine.         Both of these
encounters were, to say the least, quite unpleasant.    However, when the
crew happened upon the island of Djerba, off the coast of Tunisia, they
found a verdant land covered by the most beautiful trees the men had ever
beheld: Lotus Trees.   When Odysseus and his travel weary crew landed on
the island's shore, they first rested for most of the day.  Odysseys then
instructed two of his crewmen to search the island for food.   The next
morning, when the men still hadn't returned, Odysseus sought them out.  He
was quite worried -and understandably so- that the natives had killed
them.  Odysseus was therefore initially relieved when he saw the men
reclining under a Lotus Tree looking perfectly content.

The men had found and eaten some of the Lotus Tree fruit.  After the first
bite, they were lulled into a stupor of such blissful apathy that they
cared nothing for the homes they abandoned, the wives they once missed or
even Odysseus who had once inspired both fear and respect in them.   They
desired nothing else but to remain on that island forever so as to partake
of the Lotus fruit.   When Odysseus commanded them to rise and return to
the ship, the men merely smiled and continued to eat.     "Return at once!"
Odysseus then thundered with such passion that the ground shook.  The men
remained unperturbed.   "Go alone, dearest Odysseus," one of the men
replied softly, waving him away. "We yearn only to remain with our brethren
on the island where it is always August."    Odysseus looked around and saw
that other people were resting in the shades of Lotus trees. All of them
looked as peaceful and indifferent to life as his two men.        In a
fury, Odysseus walked over to his crew members and hoisted them up to
standing positions.   They both wailed and wept.  "Please let us remain,"
they pleaded, "Eat fruit with us and be at peace!"   Odysseus was having
none of it.   He dragged his men back to the vessel and was deaf to their
impassioned entreaties.  Once in sight of the ship, the men went so far as
to scratch at and hit Oydsseus in a vain effort to escape.  Ordinarily,
Odysseus would have punished such violent acts of insubordination harshly.
On that occasion, having recognized that his men were behaving under a
magical influence, Odysseus merely brought them back onto the ship and
departed.   After a few hours, the men stopped wailing as the effects of
the fruit subsided.

Although he was loath to admit it, Odysseus left so quickly because he
almost yielded to the temptation to eat the Lotus fruit, himself.   Such
was the intensity and long duration of his anguish at being away from his
wife Penelope and  his son Telemachus that he desperately needed the solace
that the lotus fruits would have certainly provided.   He knew that if he
did give in, he would have remained forever on that island, for no prison
is as secure as the one from which no prisoner wishes to escape.

THE SOUTHWORTH PLANETARIUM
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Julian Date:  2459263.18
2020-2021:  XCII


THE DAILY ASTRONOMER
Wednesday, February 17, 2021
Exploratorium XXV: A Saros Journey

*Location*
              Earth

*Time *
           Various points along Lunar Saros 126

To understand the Saros cycle, we must first review the circumstances that
give rise to an eclipse.

   - A *solar eclipse o*ccurs when the moon is new (at conjunction) and is
   also  at or near a node, the intersection of the moon's orbit and the
   ecliptic
   - A *lunar eclipse* occurs when the moon is full (at opposition)  and is
   also at or near a node.

Solar and lunar eclipses are not monthly occurrences because the period of
time between successive new moons (or full moons), called a *synodic month*,
approximately equals 29.5 days, which is about two days longer than a *draconic
month, *the time period  separating two successive passages of the moon
along the same orbital node, equal to 27.2 days.

                      [image: nodes.png]
Recall that the moon's orbit contains two orbits nodes, a *descending
node,* which
the moon crosses prior to moving south of the ecliptic and the *ascending
node,* which it reaches before moving north of the ecliptic.

Eclipses will also occur at different points along the moon's orbit.,
sometimes closer to Earth and at other times farther away.    Eclipses
within a given Saros cycle will always happen at more or less the same
distance.     The amount of time the moon requires to travel between points
of equal distance is equal to 27.5 days and is called an *anomalistic month*
.

Let's not imagine a lunar eclipse occurs at a given point along the moon's
orbit. Twenty seven days and a few hours later, the moon will be back at
the same node, but the moon will not quite be full again, so an eclipse
will not recur.  However, after many iterations, when the number of synodic
months, draconic months and anomalistic months are all integer values for
the first time, since that first eclipse,  the next eclipse within the same
Saros cycle will occur.  To be precise:

   - 223 Synodic months
   - 242 Draconic months
   - 239  Anomalistic months

A time period equal to 18 years, 11 days and 5 hours.        Saros cycles
don't last forever because the number of Anomalistic months that elapse
within that time frame isn't a precise integer.

Let's examine lunar Saros 126,, the cycle to which the November 19, 2021
eclipse belongs.

We'll post the diagram showing the November 19, 2021 eclipse again.
The outer circle represents the *penumbra*, the outer part of Earth's
shadow and the dark inner circle represents the *umbra*, the inner part of
Earth's  shadow.
                   [image: Lunar_eclipse_chart_close-2021Nov19.png]

The first Lunar Saros 126 eclipse occurred on July 18,1228.   That event
was a partial penumbral eclipse, meaning that the moon skimmed across the
upper part of Earth's penumbra.  Although nobody would have noticed
anything that night, it was the start of a brand new Saros cycle, one that
will continue until the year 2472.

During the next Saros 126 eclipse (July 30, 1246) , the moon's path was
slightly lower than the one immediately preceding it.  However, as the
eclipse was still a partial penumbral, it also likely happened without
anyone paying any attention to it.

Every 18 years, 11 days, another Lunar Saros 126 eclipse occurred and they
were all partial penumbrals and then penumbrals until March 24, 1625.
During that event, the moon passed low enough so that its southern limb
skimmed the upper part of the umbra.   It was the first partial lunar
eclipse.    To provide a historical context, that year Charles Stuart
(Charles I)  succeeded to the throne following the death of his father
James I.

June 19, 1769 was the date of the first total lunar eclipse in Lunar Saros
126. By that time the moon's path brought it entirely through the umbra for
the first time.      That was the year of the famous transit of Venus that
James Cook observed from Tahiti.

That total Lunar saros 126 eclipse was followed by thirteen others, the
last of which occurred on November 9, 2003.   During each successive
eclipse, the moon passed farther south.    During the November 19, 2021
event, the lower limb of the moon will not pass through the umbra.   There
will be no more total lunar eclipses in this series.

The last partial lunar eclipse in Saros 126 will happen on  June 5, 2346.
The last partial penumbral eclipse in Saro 126 will occur on August 19,
2472.

Eighteen years and eleven days later, the full moon will pass just south of
the outer penumbral shadow.    Lunar Saros 126 will pass into the ages,
like a good many others.

On May 24, 2013, the Lunar Saros 150 began.     Because it is denoted by an
even number, we know that those eclipses will be occuring at the ascending
node.   This first Saros 150 eclipse was an invisible  partial penumbral
eclipse. The last one that will occur on June 30, 3275 will be of the same
type.    Saros are born and die imperceptibly.

When regarded over long enough time periods, everything in the Universe has
a finite life span.


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