Astronomy news for the week starting Friday, March 29, 2013.
Having passed its full phase the morning
of Wednesday, March 27, our Moon begins the week by fading in its
waning gibbous phase as it heads
toward third quarter the night of Tuesday,
April 2 (or as it rises, the morning of Wednesday the 3rd). It
thereafter begins to thin in the waning
crescent, new phase not reached until the middle of next week.
Look the night of Friday the 29th to see the fat gibbous Moon
rising with Saturn directly
above (to the northwest of) it. As it orbits along its modestly elliptical path, our
companion passes perigee, where
it is closest to Earth, on Saturday the 30th.
As has been the case for some time, the planetary sky is ruled by
the two outer ancient planets (those known since ancient times), Jupiter
and Saturn, the brighter giant of the Solar
System still in Taurus north of
Aldebaran, the fainter ringed
planet in western Libra to the
east of Virgo's Spica. Jupiter now sets shortly after
midnight Daylight Time, while Saturn rises around 9:30 PM, not long
after twilight ends. They thus share the later evening sky more or
less opposed for about three hours, after which Saturn glides alone
toward its meridian crossing to the
south around 3 AM. Of the other planets,
Mercury makes a feeble attempt at visibility. Rising near-
invisibly in bright morning twilight, the little planet passes
greatest western elongation as the month of March comes to a close.
Other than the possibility that Comet Pan-STARRS might be visible
near the horizon in northwestern evening twilight, that's about it, so
we turn our sight toward the stars and the evening constellations, which with the Moon
out of the way, shine at their best. Look high as evening twilight
ends for bright Castor and Pollux in Gemini. Below it lies brighter Procyon in Canis Minor, while to the southwest glows Sirius in Canis Major. Below them all, in the deep south, sails
Argo (the Ship), only the top of which with
its three parts (Puppis the Stern,
Carina the Hull, and Vela the Sails) is visible from
northern climes. A bit to the southeast of Gemini then find Leo, the Lion, who happily roars of
the early days of northern spring.