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
               "A molecule in a bubble in a pond in a forest at the edge of
a continent on a planet tucked away amongst myriad worlds, innumerable
stars, gathered in one of billions of galaxies.    But, we're still here."



THE DAILY ASTRONOMER
Tuesday, May 24, 2016
SAM'S Triangle

Saturn, Antares and Mars!
Two planets and one star rising in early evening.   Together, they form a
beautiful triangle rising in the early evening.    Mars, having just
reached opposition on May 22, is up just before sunset.  Saturn emerges at
8:40 p.m. and then Antares follows at 8:49 p.m.  As they will all set after
sunrise, this celestial trinity will remain visible for the rest of the
night.  The image below shows their approximate configuration.


​
Antares is the brightest star in Scorpius the Scorpion, a distinctive
southern constellation that rises into prominence between mid spring and
early autumn,    Scorpius is one of those beautiful constellations which
actually resembles its namesake.  A small curved arc of stars defines its
western edge.  This arc represents the scorpion's head.  Its formidable
claws now form the adjacent constellation Libra the Scales.*   The
scorpion's curved body descends toward the horizon and then curls upward,
its eastern edge marked by a lethal stinger.

Antares, a red supergiant star so large it could accommodate more than 300
million Sun-sized spheres, appears to be the dimmest of the three bodies.
At a magnitude of 0.96, it appears 2.5 times dimmer than Saturn, nearly 17
times dimmer than Mars.  Ironically, the name "Antares" literally means,
"Rival to Mars," as they both appear red.   To our eyes, Antares isn't much
of a rival.  However, intrinsically, Mars is no match for Antares, which is
more than 800 trillion times larger in volume!  Antares' apparent dimness
is merely a result of its distance, as it is more than 440 light years
away.  Mars is about three light minutes away, and so has the advantage of
proximity.

Mars has nearly attained its maximum brightness for the year.   Although
Mars will remain visible in our evening sky throughout the remainder of
2016, by the end of the summer, it will be six times dimmer than it is
now.  By New Year's Day, it will be 15 times dimmer.  This brightness
diminishment is entirely the results of its increasing distance from both
Earth and the Sun.

Saturn is almost at its maximum brightness as well since it will reach
opposition on June 3rd.   Even at maximum, Saturn is dimmer than
Mars.       However, like Mars, Saturn's light doesn't scintillate (or
twinkle) as stars do.     Moreover, Saturn is currently slightly brighter
than Vega, so it is still easy to find, especially now as it appears so
close to both Mars and Antares.      Observers equipped with telescopes or
even binoculars might want to seize this opportunity to see a magnified
image of the planets, whose rings are clearly visible in telescopes and in
binoculars will at least appear as knobs on either side of the planet.

Some triangles, such as the Summer Triangle (Vega, Deneb and Altair) and
the Winter Triangle (Betelgeuse, Sirius and Procyon) persist for thousands
of years as they consist of stars.     SAM's triangle will be far more
fleeting, as wandering planets mark two of its points.  Find this beautiful
triplet over the next few weeks in the evening eastern or post midnight
western sky.









*Scorpius was once part of a double constellation which included Scorpius
and
Chelae the Scorpion’s Claws.   Some say that Julius Caesar detached Chelae
to form Libra the Scales, thereby establishing twelve zodiac signs, equal
to the number of months in his calendar.  According to other sources, this
detachment occurred after Caesar's assassination.  Romans chose to create
Libra in his honor.


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FROM THE CATACOMBS OF INFINITE KNOWLEDGE
Planetary occultations (when one planet moves directly in front
of the other) are quite rare.   The last time Mars occulted Saturn was
on February 7, 1522 AD/CE!
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