Astronomy news for the week starting Friday, March 1, 2013.
Sometimes the nightly sky excites, sometimes its quietness soothes;
this week it is perhaps more of the latter. We do have a Moon that
begins the week in the later stages of the waning gibbous phase, which ends at third quarter on Monday, March 4, with the
Moon out of sight. Look for the near quarter that morning. It
then spends the rest of the week as a waning
crescent whose rising approaches ever closer to the start of
dawn's light. The night of Friday the 1st, (and the morning of
Saturday the 2nd) look for Saturn just to
the east of the Moon. With the Moon passing south of the planet
during the day of Saturday the 2nd in North America, the two will
have changed places by the time they rise that evening. On Tuesday
the 5th, the Moon will pass perigee, where
it will be closest to Earth on its modestly elliptical
orbit.
Jupiter and Saturn are still "it" for the naked-eye planetary
sky. In the early evening, until it sets an hour after midnight,
Jupiter dominates the heavens. Remaining north of Aldebaran and the Hyades, the Solar System's
giant (carrying more than 300 times the mass of Earth) will
gradually pick up speed to the east against the starry background.
Then, around 10:30 PM, Saturn rises in the southeast, first to
share the sky with Jupiter and then after Jupiter sets to glide
alone toward its meridian passage
(well to the east of Virgo's Spica) shortly before 4 AM. None of
the other ancient planets (those known since ancient times) is
visible, though Mercury at least makes a bit of a splash by passing inferior
conjunction with the Sun (on the near side of the Sun) just a few hours before formal third quarter Moon on
Monday the 4th.
Sure, March is here and the passage of the Sun across the Vernal Equinox in Pisces to mark the first day of
spring is imminent. But in the early evening the Winter Triangle still glows in the
southwest. Start with the brightest star of the sky, obvious Sirius (in Canis Major). Then look to the northwest to find
bright reddish Betelgeuse (in
Orion) and to the northeast for
Procyon (Canis Minor). Farther up lies Gemini, whose classical figure traditionally holds the
Summer Solstice (even though precession has technically carried it
across the boundary with Taurus), allowing us to think of the much warmer days
to come.
