Photo of the Week.The Sun descends the afternoon sky.
Astronomy news for the week starting Friday, February 27, 2009.
Welcome to March and the scent of spring. The Moon finishes February in its waxing crescent phase as it heads
toward its first quarter, which is
passed the morning of Wednesday, March 4, just after Moonset in
North America. It thereafter waxes in the gibbous phase. The Moon and Venus
celebrate the end of February by gathering in a tight, classic
conjunction the evening of Friday the 27th, when Venus will be found just off the crescent's
upper "horn." Be sure to watch! The evening of Saturday the 28th
the pair will still make a fine sight, the Moon now well up and to
the left of the bright planet.
Venus, amazingly brilliant in western evening twilight, does not
have much time left to it as the "evening star." For now though,
it still does not set for us until after 8:30 PM. But enjoy for
now, because by the end of March it will be gone from view, as it
passes between us and the Sun (though not
directly) to become a "morning star." As a prelude, the planet
enters
retrograde (westerly) motion against the background stars the
night of Wednesday the 4th, turning in direction toward the
Sun.
For a time sharing the sky with Venus,
Saturn now rises just after Sunset as it closes in on solar
opposition next week. The ringed planet, moving slowly retrograde
in southeastern Leo, now crosses
the
meridian to the south just after local
midnight. If we wait 'till dawn, we might get a first glimpse of
Jupiter, which now rises just after the
commencement of morning twilight. Moving in a stately fashion (as
befits the king of the gods and planets) at the rate of one zodiacal constellation to the east
per year, Jupiter now resides among the stars of northern Capricornus. To finish the planetary
tale, on Sunday the 1st,
Mercury and Mars rather invisibly pass conjunction with
each other. Less than a degree apart, the red planet will be to
the north, the pair down and to the left of Jupiter.
Be sure to follow Comet Lulin,
which is easily visible in binoculars.
As the week begins it is just southeast of Regulus in Leo, while on the night
of
Saturday the 28th, it will be to the west of the star.
Over the week it will move westerly into Cancer, and the nights of Thursday, March 5,
and Friday the 6th, it will appear
just to the south of the Beehive
Cluster. The comet appears to be a new visitor from the vast
Oort
Cloud of comets that extends a good way to the nearest star,
the comets -- the debris of planet formation -- scattered out of
the plantary system
billions of years ago by the giant planets.
While winter's eye is drawn to Orion, look to the northeast of the Hunter to admire Gemini, the most northerly of
zodiacal
constellations, and the classical home to the Summer Solstice (which is really now just over the
artificial border into eastern Taurus, the result of the 26,000 year wobble of the Earth's rotation axis).
At the top of the constellation shine the bright stars Castor and Pollux, Castor (on top) the brightest of the second magnitude
stars.
