Astronomy news for the two-week period starting Friday,
September 15, 2006.
Our fortnight fits between the two lunar quarters. Beginning with
third quarter
on Thursday the 14th, the Moon slims in its waning crescent phase to new on
Friday the 22nd, then fattens in the waxing crescent to
first quarter on Saturday the 30th. Note that the dawn waning
crescent faces down and to the left, while the evening twilight
waxing crescent faces down and to the right, in both cases toward
the invisible Sun. The morning of
Monday the 18th, the Moon will rise almost directly above
Saturn, while the following morning it will be down and to the
left of the ringed planet and directly above Regulus in Leo. During the second week of our period, watch the
crescent climb toward
Jupiter. The night of Monday the 25th, the Moon will be to the
southwest of the giant planet, while the following night it will
have flipped to the other side. Then admire the near-quarter just
to the west of Antares in Scorpius the evening of Wednesday the
27th.
In the middle, the new Moon will eclipse the Sun, though unfortunately not as seen
from North America. Indeed, plowing right down the middle of the
south Atlantic Ocean, the eclipse path seems to avoid almost all
land masses. No matter. The Moon is near apogee,
so the eclipse is "annular,"
that is, the Moon cannot completely cover the solar disk, allowing
a bright ring of sunlight to be seen, making the event
scientifically far less interesting.
It is the Earth
that takes center stage, as at 11:03 PM Central Daylight Time on
the night of Friday the 22nd (12:03 AM EDT Saturday the 23rd, 10:03
MST back on the 22nd, 9:03 PM PDT, 8:03 PM Alaska, 6:03 PM Hawaii),
the Sun crosses the autumnal
equinox in Virgo and
astronomical fall begins in the northern hemisphere. On the
night of the 22nd, the Sun will set very close to the west point of
the horizon, while the morning of the 23rd it will rise very close
to due east. At equinox crossing
it glides overhead at the equator, while technically setting at the
north pole
and rising at the south pole
(the actual dates respectively delayed and advanced by the Sun's
half-degree angular diameter and upward refraction by the Earth's
atmosphere).
The only bright planets to admire now are the two largest. But
don't look too late to find Jupiter, as it sets around 9 PM. Then
comes a long gap until Saturn rises around 3:30 AM. For all
practical purposes, Venus
is lost to morning twilight.
In early evenings, Sagittarius
rides low above the southern horizon. The Archer holds two beloved
asterisms (small informal constellations), the Teapot (its "tea"
the glorious Milky Way) and
the upside-down five-star Little Milk Dipper. Dipper figures
abound in the sky. In the far north are both the Big and Little Dippers of Ursa
Major and Minor, while the brighter stars of the Taurus's Pleiades star cluster make
another fine, though much smaller, one.
