Astronomy news for the two week period starting Friday, May 27,
2011.
We begin our fortnight with the waning
crescent Moon, which heads towards new on the afternoon of
Wednesday, June 1. Your last view of the crescent in eastern
twilight will be on the morning of Tuesday, May 31, after which it
will appear as an ultrathin waxing
crescent during early western twilight the evening of Thursday,
June 2 (in both crescent phases the nighttime sides of the Moon
aglow with light reflected from Earth). Growing fatter, the Moon
finally passes first quarter on Wednesday
the 8th during evening twilight for much of North America. We then
get to see a bit of the waxing gibbous.
Skylights begins on Friday the 27th with the Moon at its apogee, where it
is farthest from Earth.
Watch the mornings of Sunday, May 29th through Tuesday the 31st to
see an amusing interplay with the planets, first with
Jupiter (the Moon above the rising planet), then Mars and
Venus (the Moon above them and to the left of Jupiter, and
finally passing above nearly invisible Mercury. Switching to the evening sky, the growing
crescent will grace southern Gemini below Castor
and Pollux on Friday the 3rd, then
will appear down and to the left of the stars the following night
and immediately to the left the night of Sunday the 5th. A few
nights later, on that of Thursday the 9th, we find our Moon to the
southwest of Saturn and to the west of Spica, the three making a fine
triangle.
This new Moon is a bit of a special one, as it crosses in front of
the Sun to produce a
solar eclipse. But don't
bother watching, as it is both partial and polar. Only northern
Alaska, northern Canada, Greenland, and Siberia will see much of
anything.
As is obvious from the progression of the waning crescent, the four
morning planets no longer clump together but instead are now in a
nice line, starting with Jupiter up and to the right, then
proceeding down and left through Mars, Venus, and Mercury, the last
three difficult-to-impossible to make out. But it is easy to
admire Jupiter, which rises shortly before the start of dawn.
The star of the show, though, remains
http://saturn.jpl.nasa.gov/">Saturn, which during the middle of
our fortnight crosses the meridian to
the south just past sundown, so will appear in the southwest after
darkness falls, not setting until around 2:30 AM, shortly before
Jupiter rises. Still set to the northwest of Spica, as our period
ends the ringed planet will stand but a quarter of as degree from
much fainter (third magnitude) Porrima (Gamma Virginis, itself a
remarkable telescopic double star). Finally,
in lesser planetary news, Neptune begins
retrograde motion (to the west against the stellar background
near the Aquarius-Capricornus border) on Friday the
3rd.
Two icons of the sky round their respective poles, the Big Dipper in the north, the Southern Cross at about the same
polar distance in the south. From the tropics you could watch them
both, the two on a great circle that connects them to the North and
South Celestial Poles.
