June 2012 Sky from the Keeble Observatory
Reminder! The Keeble Observatory at Randolph-Macon College will open for public
viewing of the transit of Venus at 5:30 pm EDT on June 5th, weather permitting.
Last chance until 2117 to see this phenomenon! We expect “first contact” about 6:04
pm, and will follow the transit until we lose the Sun behind our local horizon (which,
unfortunately, includes trees and buildings!). As our calculations are refined,
we’ll post updates on the Keeble Information Line at 804-752-3210.
You’ve probably heard by now the notion that the Mayan calendar predicts the end
of the world on December 21 this year, so perhaps the coming transit is really
the last one! Of course, we’re also used to the occasional end-of-times prophesy
from various self-declared prophets, so maybe this one is like the others. Let’s
see where some of this nonsense originates. It starts with counting.
The Maya were a pre-Columbian civilization in Mesoamerica, who used a system of
base-20 numbers. (We use base-10, or decimal numbers. Computers use base-2, or binary,
while computer code is usually written in base-16, or hexadecimal.) They were careful
observers and recorders of astronomical phenomena, and so were aware of cycles of
eclipses and sidereal periods of the naked eye observable planets. In base-20, each
place holder is 20 times the previous. Curiously, they made an exception for the
second place holder, which only counted to 18. 18 times 20 is 360 – approximately
the length of a year.
The calendar is a complex mixing of several cycles or counts. There is a
260 day count, known as the Tzolk’in, which may have originated with the
earlier Olmec civilization and would have been passed on to their Maya successors.
At the Olmec site of Izapa in Mexico, there are 260 days between the Sun’s zenith
passages (directly overhead). The Tzolk’in was combined with a 365 day cycle known
as the Haab to form a synchronized cycle of 52 Haabs called the Calendar Round.
They also maintained a 584 day cycle to track the motions of Venus, as well as a
series of 13 and 20 day counts.
For really long time periods, they used the Long Count, and it is a misunderstanding
of the Long Count which gives rise to the apocalyptic foolishness. The Maya word
for day is k’in. Twenty k’ins make a uinal. Eighteen uinals make a
tun, and twenty tuns are a k’atun. Twenty k’atuns are a b’ak’tun.
Got it? That’s 144,000 days, or a little over 394 years. The cycles extend for another
four multiples of 20 to form the full long count of over 23 billion days, with comes
to exactly 63,123,288 years. The long count calendar begins with a mythological
event in what our calendar would identify as August 11, 3114 BCE, so we haven’t
even made it through 13 b’ac’tuns, let alone all the way to the end of the Long
Count. However, the 13th b’ac’tun ends on December 21st –
and that’s the purported end of days!
According to Sandra Nobel, who is executive director of the Foundation for the Advancement
of Mesoamerican Studies, the end of a b’ac’tun would be a time for celebration,
not a prediction of doom. Although, several bad movies and worse web sites about
2012 may fit the definition of disaster!
Lunar phases for June: Full Moon on the 4th, at 7:12 am; Last
Quarter on the 11th, at 6:41 am; New Moon on the 20th at 11:02
am; First Quarter on the 26th at 11:30 pm.
Pre-dawn hours in June are not a good time for planet watching! Mars sets about
4 hours after sunset early in the month, and Saturn follows two hours later. By
the end of June, they are setting two and three hours after sunset. Jupiter, Venus,
and Mercury are lost in the Sun’s glare. Evenings will afford better opportunities
to view Saturn and Mars. Both will emerge from twilight and remain visible for several
hours. Saturn starts the month due south, about 45 degrees above the horizon, Mars
is about the same altitude but to the southwest. Both will move more to the west
(relative to the horizon) as the month passes, appearing southwest and west-southwest
respectively by month’s end.
Our overhead view about three hours after sunset at midmonth finds the constellation
Hercules at zenith. If it’s not too hazy (a summer viewing inconvenience for central
Virginia) binoculars will allow you to see the globular cluster M13 along the western
edge of the square marking the familiar constellation. About 10 degrees east of
zenith you’ll find the constellation Lyra, marked by the bright star Vega. Your
binoculars should allow you to pick out the Ring Nebula, and the interesting “double
double” binary star. The Big Dipper asterism in Ursa Major is prominent to the northwest.
Following the arc of the “handle” back to the west will bring you to Arcturus, about
55 degrees above the horizon. That bright star below and to the left of Saturn is
Spica, in the constellation Virgo.
Turning your binoculars to the south will open a rich field of clusters as you look
toward the center of our Galaxy in the constellation Sagittarius. To the right of
the familiar “teapot” is bright red Antares, which means “against Mars.” And to
the east you’ll see the familiar Swan – Cygnus – marked by bright Deneb at the swan’s
tail, and the beautiful binary Albireo at the head. Check it out with binoculars
or a small telescope.