[image: unnamed.png]
*Orion:*    *The Great Hunter*
What better figure to inaugurate the new semester than Orion the Great
Hunter, whose namesake constellation is just now ascending in the pre-dawn
eastern sky:  heralding summer's end and winter's inevitable return?
 Well, better in the sense of appropriate, not morally superior.    Of all
the characters populating the mythological Universe, Orion is arguably one
of the most complicated.  Neither a paragon of virtue nor the embodiment of
malevolence, Orion engaged in both laudable and detestable acts, as we
shall see.     Though his paternity is disputed, most authorities agree
that his father was the ocean god Poseidon.   Strangely, he had no mother,
but instead was conceived when Poseidon made water on a bull-hide, hence
the name "Orion," which is closely related to the word "urine."
Poseidon buried the hide and a few days later, the infant Orion emerged.
 Poseidon gave the child to King Hyrieus -his son by the Pleiad Alcyone- to
raise as his own.   Hyrieus was unmarried, childless and consequently quite
lonely.   He received the baby Orion gladly for he knew that the infant
would prove a most pleasant companion.     (Hyrieus would later take the
nymph Clonia as a consort and by her he eventually sired future Thebian
kings Nectus and Lycus.)  Orion quickly grew into a prodigiously strong and
unusually handsome man.    King Hyrieus proved a kind and loving father.
 In turn, Orion matured into a dutiful and caring son as well as a fearsome
hunter, whose game-slaying exploits became widely known throughout many
lands.     Oinopion, King of Chios, learned of this hunter and sent a
messenger to Hyrieus requesting Orion's service.    His kingdom had been
terrorized by many formidable beasts and the king was at a loss.   He
offered Orion and Hyrieus half his wealth in exchange for Orion's
services.       Orion accepted the offer with alacrity, for he was always
eager to seek out new prey.    "We have a boat already prepared," the
messenger told him.    "No need," Orion responded. "I'll walk to Chios."
 To the messenger's astonishment, Orion strolled quickly out onto the sea
and walked along the surface. Poseidon had bestowed this water-walking
ability onto Orion at his birth.        Once in Chios, Oinopion told him
where he would find the creatures that had been stalking his people.
With his club and sword in hand, Orion raced out into the kingdom and
sought out each beast.  He dispatched each of them so quickly that by the
end of the first day he had all their cadavers in a pile.     When Oinopion
arrived to survey the corpses, he was accompanied by his beautiful daughter
Merope.    Orion became so infatuated with Merope that on the following
night, when the grateful king held a banquet in Orion's honor, the drunken
hunter attempted to assault her.  The king's soldiers intervened and,
though they were no match for a sober Orion, were able to restrain him.
  The furious king not only withheld the treasure he promised Orion, but
also blinded him with a sword.  Orion stumbled miserably off Chios and
walked across the sea to the island of Lemnos where Hephaestus, the god of
fires and forges, greeted him.    Hephaestus told Orion that he could find
a cure for his blindness by walking across the sea toward the far east.
 Once there, Helios Hyperion would restore his vision with the Sun's light.
To ensure that Orion wouldn't lose his way, Hephaestus ordered his servant
Cedalion to guide the hunter to his destination.     Cedalion dutifully
hoisted himself on the giant's shoulders and directed him to the far east.
   After having regained his sight, Orion promptly returned to Chios,
determined to avenge himself on Oinopion.    Anticipating the giant's
return, Oinopion had ordered his servants to construct an underground
shelter in which the King lay hidden upon Orion's return.      Despite his
implacable rage, Orion ultimately abandoned his pursuit of Oinopion, whom
he could not locate.     As he lay sleeping against the shore, he dreamt
that King Hyrieus had been abducted by a bull and conveyed to the island of
Crete where he was to be sacrificed to Poseidon.        Orion hastened
across the sea to Crete in an effort to save the king.    Yet, on his
arrival, Orion learned that the King wasn't present or in danger.
 Though initially angered that he behaved so rashly in reaction to a dream,
Orion soon found that Crete was a lush land rife of great forests and
teeming with game.        Forgetting all else, Orion roamed through Crete
slaying one creature after another for the sheer sport of it.       As had
happened on Chios, Orion soon gathered a large pile of cadavers on Crete,
but was unsatisfied for so many other creatures remained uninjured.    He
resumed his hunt and by the first nightfall had slain more than a hundred.
     As he prepared to nap next his collection of corpses, Orion declared,
"Such a great hunter am I that I shall soon slay all the beasts in this
land and in all the others!"      Unfortunately for Orion, Artemis, goddess
of the moon and wild animals, had been passing through the sky in her
chariot and heard this boast.    Terrified that this reckless hunter would
actually attempt to slay all the animals, Artemis summoned Scorpius the
Scorpion down to Earth to kill Orion.         Scorpius appeared in the very
glade where the hunter slumbered.   The scorpion's motion awakened Orion,
who immediately attempted to engage the immense scorpion in combat.    The
fight didn't last long, for the scorpion adroitly evaded his adversary's
blows and nipped his ankles.    The stricken Orion collapsed to the ground
and within an instant was dead.   At Artemis' behest, Scorpius dragged the
hunter's body over and hoisted it onto the top of the cadaver pile.   It
was said that Poseidon's grief at his son's death was unbounded and would
have fought with Artemis, herself, had Zeus not intervened.       Although
he was prevented from avenging his son's death, Poseidon did place Orion in
the night sky and adorned his constellation with some of the brightest
stars.   Artemis honored Scorpius in the same manner, by elevating it into
the heavens.     However, at Zeus' insistence, Orion and Scorpius were
arranged so that they would occupy the sky together, so as to prevent a
resumption of violence.  Consequently, when Scorpius is visible in the sky,
Orion is absent and vice versa.      Now, in extreme late summer/early
autumn, Scorpius sets in the early to mid evening while Orion rises well
after midnight.

THE SOUTHWORTH PLANETARIUM
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Founded January 1970
Julian Date: 2459093.16
2020-2021:  I

THE DAILY ASTRONOMER
Monday, August 31, 2020
Remote Planetarium 79:  The Solar Apex

Welcome back!
A new semester has begun,   Granted, this new school year will likely prove
to be quite different from any of the previous semesters, owing to the
continued Covid-19 pandemic.  For this reason, the Remote Planetarium
-which started on March 30th- will continue until December 21st.

Just before we ended the first "semester," we started the next section of
the astronomy course involving "galactic astronomy."  Naturally, we will
continue this next phase today with a discussion about the "Solar Apex,"
the direction toward which the solar system is moving in the Milky Way
Galaxy.

[image: Sun's Approx. Orbit around Milky Way (08Nov2018).jpg]

Recall that the Sun and 300 billion other stars comprising the Milky Way
Galaxy are not stationary, appearances notwithstanding.   The Sun and the
other stars are moving through the Milky Way at high velocities, the values
of which are location dependent.    (We're not moving as quickly as those
stars close to the galactic nucleus.)   Though they seem static even over a
human lifetime, the constellations will slowly change over thousands of
years as a consequence of these motions.     Where is the Solar Apex:
toward which constellation are we moving?

Before we address this question, we must first introduce what for us is a
new term:    the *"Local Standard of Rest."     *Despite its name, the
Local Standard of Rest (LSR) refers to the average motion of stars within a
100 parsecs of the Sun.  (One parsec equals 3.26 light years.)     To
understand the LSR, first imagine that all the stars were stationary.
In this instance, defining the LSR would be delightfully simple.      The
plane along which the stars were aligned would define it.     If all the
stars are moving, how can one establish a "resting plane?"    The motion
directions of the proximate stars are measured and then averaged.    The
resting plane is established by these different motions.

[image: unnamed.gif]

The graphic above depicts a simplified view of the LSR with the Sun
occupying the region's center.   Relative to this LSR, the Sun is moving
toward the apex, a region within the constellation Hercules, just south of
Vega, the brightest star in Lyra the Harp.

[image: solar-apex.gif]

While the Sun is moving at 137 miles per second relative to the North
Galactic Pole, the position of which is approximated by the supermassive
black hole within the nucleus, its motion toward the apex is merely 10.5
miles per second, about 1/13th that of its speed relative to the NGP.

As we expand our view field to encompass this galaxy, those around and the
myriad super clusters of which our enormous Milky Way is a part, we should
at least know toward which direction the Sun and its retinue of attendant
bodies are moving.

Tomorrow, we keep moving...

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