The entire week sees the waning of the crescent Moon, none of the
quarters passed, as last quarter took place on Thursday, April 4,
and new Moon will not occur until Friday, April 12. The quartering
of the Moon's orbit, plus the moving "seven bodies of the sky" (the
Sun, Moon, and 5 naked-eye planets) surely led to the concept of
the week. The time-period of the month comes from the 29.5 day
period of the phases. The months of both the Moslem and Jewish
calendars adhere to the 29-30 day month, while the civil calendar
(from old Rome) stretches
the months to fit the year. The Moon also gives us the date for
Easter, now past, which takes place on the first Sunday following
the first full Moon past the time of solar passage across the vernal equinox.
As the crescent Moon descends the early morning sky, it passes four
degrees south of the two outer planets,
Uranus and
Neptune, which (in Capricornus)
have now well-cleared the Sun, the Moon gliding by Neptune on
Saturday the 6th, Uranus on Sunday the 7th. While the two planets
are still more or less in the same direction, Uranus, to the east
of Neptune, is ever so slowly pulling away from its sister. Given
the long orbital periods of the two (84 years for Uranus, 165 for
Neptune), we will not see them in this configuration again for
another 170 years.
Uranus and Neptune are hard to see, though Uranus is in fact just
visible to the naked eye. In contrast, two brilliant planets
dominate western evening skies.
Venus is unmistakable in bright twilight, while much higher
Jupiter in Gemini lasts until
after midnight. Between the two is fading Mars
and bright
Saturn, which are slowly approaching each other in the
constellation Taurus, Mars situated
south of the Pleiades, Saturn
north of the Hyades and
Aldebaran.
The shorter period of Jupiter (12 years) and Saturn (29.5 years)
allow them to rendezvous much more frequently, the two planets
passing each other every 20 years. A passing does take place this
week as little
Mercury hides behind the Sun, the planet in superior
conjunction on Sunday the 7th.
North of Jupiter find Gemini's pair of bright stars, Castor and Pollux, which look back at us like a
pair of celestial eyes. The most northerly constellation of the
zodiac, Gemini holds the summer
solstice, which is now rather well-marked by Jupiter (the solstice
8 degrees to the west of the bright planet). To the
east of Gemini lies dim Cancer (the
Crab), marked best by the fuzzy patch that binoculars reveal as a
fine cluster, the Praesepe
or Beehive. Farther to the east find that true harbinger of
spring, Leo the Lion, whose front end is
graced by the first magnitude star Regulus. More easterly yet, toward the
southeast at 9 PM or so, see Spica in
Virgo climbing the sky. Between the
two stars is the autumnal equinox, where the Sun will be on the
first day of autumn.
