Astronomy news for the week starting Friday, Sepember 4, 2009.
The fortnight features a total Moon-fade, which starts on Friday,
September 4 with the full Moon and ends on
Friday the 18th with the Moon going through new, when it is more or less between
us and the Sun
(though not directly, as otherwise we'd have an eclipse). In between, it wanes first
through its gibbous phase, then passes third quarter on Friday the 11th (thus
splitting our two-week period), then at last goes through the ever-
thinning waning crescent.
The night of Saturday the 12th, the Moon will be seen to the west
of Mars, while the
following night it will be to the east of the red planet. In
between, the Moon will actually occult it, though the event takes
place in the daytime and is not visible from North America. Much
better is the near-classic pairing of the waning crescent with Venus the morning of
Wednesday the 16th, when the brilliant planet will be just down and
to the left of the Moon. Leo,
climbing out of twilight, adds to the show, as first magnitude Regulus will be below Venus, the
three -- Regulus, the Moon, Venus -- making a fine triangle. The
last view of the thin crescent then comes on the morning of
Thursday the 17th.
In less-visible news, Mercury
begins its retrograde (westerly against the stars) motion on
Saturday the 6th, the Moon passes north of Uranus
on Saturday the 5th, and the Moon passes perigee, where
it is closest to the Earth, on the morning of Wednesday the 16th.
By odd coincidence (or in astronomy, not so odd, as these things happen a lot),
Uranus goes through opposition to the Sun on Thursday the 17th only
eight hours before Saturn, which has been disappearing into twilight,
goes through solar conjunction. More invisibly, Pluto, now in far northwestern
Sagittarius, ceases its little
retrograde movement on Friday the 11th.
After all this, the big show is in the evening, with Jupiter now well up in the southeast at the end
of twilight, crossing the meridian to
the south around 11 PM Daylight Time, then setting just before
morning twilight begins to light the sky. By that time, Venus is
up in the east, rising around 4 AM and beating twilight by a good
hour. In between, Mars becomes a sort-of evening object by rising
at local midnight (1 AM Daylight). Jupiter still resides in far
northeastern Capricornus, Mars
moves along in southern Gemini,
and Venus lights the sky southeast of Cancer's Beehive
Cluster.
It's Vega season, in mid-northern
climes Lyra's brightest star and
the northeast anchor of the Summer
Triangle passing nearly overhead in mid-evening. The big
triangular pattern is fulfilled by Deneb of Cygnus at the northwest apex and Altair of Aquila at the southern, the constellation of the Eagle the gateway
to the southern Milky Way as it pours
through Scutum and into
Sagittarius.
