The Moon waxes through its gibbous phase this week, reaching
toward full phase, which it will attain on Friday, April 26. On
Sunday the 21st and Monday the 22nd the Moon will be well-ensconced
amid the stars of Leo, while on Thursday
the 25th it will pass a bit north of Spica in Virgo. In between, on Wednesday the 24th, the Moon
will lie just to the east of the autumnal equinox, where we will
find the Sun next September 22nd. The bright Moon will make it
difficult to see morning's
Comet Ikeya-Zhang, which is coursing through southern
Cepheus.
While the Moon will dominate the eastern and morning skies, the
planets rule the heavens of western evening. There is no trouble
at all finding brilliant Venus,
which is now setting after the end of twilight, around 9:45 PM
Daylight Time. Using Venus as a guide, then admire the five
ancient planets, those known since ancient times, as they line up
along the ecliptic, outlining it rather closely rather like a
circle thrown up on a planetarium dome. Up and to the left -- to
the east -- of Venus is Mars,
which has faded nearly to second magnitude, but is still
recognizable by its reddish color. Farther up and to the east is
much brighter "zeroth" magnitude Saturn.
Making its appearance after its superior conjunction with the Sun
on April 7 is Mercury,
which will be well down and to the right of Venus and near the
twilight horizon. Finally, high above, looking down on all the
action, and keeping a bit apart, is bright Jupiter,
which graces the sky in Gemini until just after 1 AM.
There is more to see in the neighborhood. At the beginning of the
week, Venus shines a bit down and to the right of the Pleiades star cluster in Taurus. As Venus climbs higher and
Taurus sinks in the west, the two will pass each other, Venus to
the south, near week's end. Mars, on the other hand, now makes a
fine contrast with similarly-colored Aldebaran in Taurus, the planet to
the right of the star on a line nearly parallel to the horizon.
Saturn is above the Hyades and Aldebaran, Saturn, aldebaran, and
Mars making a fine triangle.
Keep watching this assembly as it all more-or-less gathers
together. For a given time of night, Venus and Mercury will climb
up, whereas Mars, Saturn, and Jupiter will descend, causing three
fine conjunctions to take place in early May. Such alignments are
not all that uncommon, and have no significant effect on the Earth
other than calling people out to watch and to become interested in
the night sky and in the science of astronomy.
