THE SOUTHWORTH PLANETARIUM
207-780-4249      www.usm.maine.edu/planet
70 Falmouth Street     Portland, Maine 04103
43.6667° N                   70.2667° W
Founded January 1970
Julian date:  2457658.16
         "It is said that writing is a lonely occupation.     The exact opposite holds true because any mind mired in its own imagination exists, even if for a few moments, wholly untethered within the dynamically active and vibrantly iridescent worlds of its own conjuring.    That which is desired is effortlessly summoned; that which has for so long lain dormant is awakened;   Vague figments crystallize into sentient souls.   The sinister phantom and fantastic spirit alike will enliven the  unfrequented wield and remote mountain summit.   From the thinnest winds one can fashion the richest  realms running parallel to and juxtaposed with one's own life.   And, in the briefest moments, one can almost sense its presence and, irrationally and wonderfully, think it actually tangible."



THE DAILY ASTRONOMER
Monday, September 26, 2016
Week 4 Night Sky Calendar:   
September 26 - October 2, 2016


The first full week of autumn and, happily, the world hasn't yet succumbed to hopeless despair.   And, after all, why should it?   Who doesn't secretly adore the brisk morning winds across crisp  frost coated grasses and the muted ember lights aglow beneath the shadowed gables?    Those that not so long ago darted rapidly across August's skin-scorching beaches now gather woolen garments around them, as though already bracing themselves against winter's unrelenting tempests.       The canopy darkened forests slowly shrug away their foliage that will slowly dissolve into the receiving soil before the crystalline snows enshroud it.   Meanwhile, we sensible people have found shelter in far away alcoves equipped with thermostats capable of imparting confession-inducingly high temperatures at the flip of a switch.    Add to that an inexhaustible spigot issuing forth torrents of sweet frothing flavored coffee and all we can say is, "you hunter gatherer types have fun outside. See you in late June."

Those intrepid souls who do venture out will, as always, behold a firmament abounding in wonders this week.   For instance, we'll watch Scorpius and Sagittarius begin the night well over in the southwestern sky.       These two splendid summer constellations won't remain on our evening stage much longer.   As they disappear into the dusk, so, too, will the messier objects within them.   You know, this school year we're hell-bent on visiting every object within Messier's celebrated catalog.       Before we begin with our night sky calendar, we wanted to stop briefly by a magnificent Messier object, M6, the Butterfly Cluster


​This image shows Scorpius and Sagittarius traveling along the southern evening sky.   Within this field we find the "Butterfly Cluster,"just north of the scorpion's tail.  Named for its vague resemblance to a butterfly's wings, the Butterfly  is an open cluster about 1600 light years away.     


​The Butterfly Cluster (M6) an open star cluster that Charles Messier included in his catalog in 1764.   This open star cluster is about 1600 light years away in the direction of Scorpius the Scorpion.      It contains hundreds of component stars and is approximately 12 light years in diameter.    Image: Ole Nielsen 

Even though Charles Messier cataloged the Butterfly Cluster in 1764, it was actually discovered more than a century earlier by Giovanni Battista Hodierna. (See "From the Catacombs of Infinite Knowledge.")      The Butterfly Cluster was so named because it vaguely resembles a butterfly.     M6 is a splendid example of an open or galactic cluster,  It consists of a few hundred stars within a spherical shell 12 light years in diameter.   Although one can observe this cluster through a small telescope, one would have to venture outside early, this Messier object and its host constellation Scorpius are low in the southwestern evening sky tonight.

Now, to proceed with this week's night sky calendar

MONDAY, SEPTEMBER 26:   JUPITER IN SOLAR CONJUNCTION
Don't bother searching for Jupiter right now.  The giant world is swinging around the other side of the Sun, well out of our sight.     Today, Jupiter will be on the far side of the Sun relative to Earth: a configuration called "superior solar conjunction."  The two types of conjunction are superior and inferior.  A planet is in inferior conjunction when it is between Earth and the Sun.   Only the inferior planets, Mercury and Venus, can be in inferior solar conjunction.   All of the planets, inferior and superior, can be in superior solar conjunction.     If you doubt this statement, imagine Earth and Mercury revolving around the Sun.   Hold Earth steady and let Mercury complete one orbit.    You should see in your mind a moment when Mercury will be on the far side of the Sun relative to Earth.

WEDNESDAY, SEPTEMBER 28:  MERCURY AT GREATEST WESTERN ELONGATION (17.9 DEGREES)
Mercury is a morning sky sight this week.   Although it seems counter intuitive, remember the following:  when an inferior planet is at western elongation, it will be visible in the eastern pre-dawn sky.   When an inferior planet is at eastern elongation, it will be visible in the western early evening sky.       Look for Mercury in the early morning eastern sky!  

THURSDAY, SEPTEMBER 29:   MOON 0.67 DEGREES SSW OF MERCURY
The thin, waning crescent moon lingers close to Mercury.     At the very southern tip of the world, the moon will appear move directly in front of Mercur which is called an "occultation."   However, this occultation won't truly be visible as it will occur in daylight.   We we will see Mercury and the sliver moon less than a degree apart against the brightening morning twilight: a sight almost as dramatic as a bona fide lunar occultation.  

SATURDAY, OCTOBER 1:  NEW  MOON
Also called "conjunction."     As October begins, so, too does another lunar cycle.  Today, we commence lunation cycle 1160.

PLANET WATCH

MERCURY:(Host constellation - Virgo)  becomes visible in the pre-dawn sky by the third week of September.   It is elusive, as always, but by the end of September grows brighter than Saturn and Mars.   VERDICT:   Wait until the very end of September to see Mercury in the early morning eastern sky.

VENUS (PICK PLANET!)  (Host constellation - Scorpius) Venus maintains a constant brightness throughout September, but, of course, remains brighter than all the other planets and all the night sky stars.    Even though Venus sets during the very last twilight phase this month, it is still a brilliant western sky object and easy to find if you have a low western horizon.
VERDICT: If you're out at dusk, seek out Venus all month!

MARS:   Mars had its time in the limelight in May when it reached opposition.  Although it remains in the western evening sky for the rest of the year, it will diminish sharply in brightness through autumn.    VERDICT:     See Mars in the southwestern early evening sky each night this month.       As autumn ages, Mars will grow dimmer..

JUPITER: (Host constellation - Jupiter)  Not visible this month!    This bloated gas giant returns to the pre-dawn eastern sky by mid October.    VERDICT:  Well.....please wait until late next month.

SATURN:  (Host constellation - Libra)  Is dimmer than Venus, Mars and, by late September, will also be dimmer than Mercury.  This planet will vanish into the dusk by November.  Now, it rises about four minutes earlier each night.   VERDICT:   Find Saturn in the early evening this month.   It will become much harder to find in October as it approaches its hiatus.

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FROM THE CATACOMBS OF INFINITE KNOWLEDGE
Giovanni Battista Hodierna,  the forgotten compiler

This school year, we are celebrating Charles Messier, the French astronomer whose catalog of celestial objects remains with us even 200 years after his death.     Even though Messier was a comet hunter by avocation, he is best known as a compiler of the catalog be developed for the benefit of other astronomers who might confuse these objects for comets.    

​Giovanni Battista Hodierna, an obscure Italian astronomer who compiled
a catalog of 40 objects that astronomers might confuse for comets.  His work
predated Messier's catalog by more than a century, but was little regarded by the
astronomical community.   Many astronomical historians believe that Messier
never even heard of the Hodierna catalog.

However, we should give some mention to the Italian astronomer Giovanni Battista Hodierna (1597-1660).    Don't worry if you've never heard of him, for he is one of astronomy's most obscure figures.    Like Messier, who was born seventy years after his death, Hodierna realized that some night sky objects could be mistakenly cataloged as comets.    He compiled a list of 40 objects for the benefit of other comet-seeking sky watchers.     Though his catalog was innovative, it lapsed into obscurity,  Even Charles Messier, whose catalog we celebrate this year, likely never knew of its existence.       However, more than a century before the final publication of Messier's catalog, a long forgotten Italian astronomer produced its precursor.
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