Skylights featured five times on Earth Science
Picture of the Day: 1
, 2
, 3
, 4
, 5
Photo of the Week. A perfect cloudless sunrise
coupled to absorption in the Earth's
atmosphere beautifully separates the colors of the solar spectrum from red near the horizon
to deep blue overhead.
Astronomy news for the week starting Friday, April 21, 2006.
Having just passed last (third) quarter, the Moon wanes in its crescent phase to new, which is
invisibly passed during mid-day on Thursday, April 27th.
Watch the morning sky for developing earthlight on the lunar nighttime
side. Two days before new, the Moon goes through perigee
, where it is closest to the Earth, the pairing raising
particularly high and low tides
at the coasts.
The Moon then takes a bead on four planets in a row (though only
one of the events is really visible). On the night of Friday the 21st, it goes
four degrees south of Neptune, and then just two days later, a bit over
a degree south of Uranus, both of the outer planets (respectively in
Capricornus and Aquarius) having well cleared the Sun. The big event is
a nice pairing of the Moon with
brilliant Venus the morning of Monday the 24th, the planet
and Moon rising just as twilight begins, 4:30 AM (Daylight Time).
On the morning of Wednesday the 26th, the Moon passes well north of Mercury, but both are so low as to be washed out
by bright twilight.
It is the evening that now holds most of the planetary treasures.
To the west, find
Mars in western Gemini far
above disappearing Orion, the red
planet setting at local midnight (1 AM Daylight Time). East of
Mars (but still in the western sky), in Cancer (one zodiacal
constellation over), is Saturn, which
sets an hour and a half later. Then toward the southeast, Jupiter
(in Libra) makes a mark by
rising during mid-twilight, around 8:30 PM Daylight Time.
The fading Moon will not terribly bother the viewing of the Lyrid meteor
shower, which peaks the morning of Saturday the 22nd, its meteors
appearing to radiate from the constellation Lyra just to the south of Vega. While not the best shower of the
year, it still reliably produces perhaps 10-15 meteors per minute,
the event caused by the debris of Comet
Thatcher of 1861 hitting the Earth's atmosphere. The shower is
capable of brief bursts of activity.
Mid April sees western Hydra, the
Water Serpent (the longest constellation in the sky), crossing the
meridian to the south in early evening. Far below its brightest
star, lonely Alphard (itself seen
to the south and a bit west of Leo,
the Lion), the last of Argo the
Ship glides away to the west, Vela
(its sails) gently rippling in the southern breezes just above the
horizon.
