Astronomy news for the week starting Friday, April 24, 2009.
Moon begins our week, Friday, April 24, right in its new phase.
The whole week is then devoted to evening's waxing crescent, the Moon not passing first quarter until the afternoon of Friday,
May 1, when it can be seen rising in North America. The timing is
such that you might be able to spot an especially thin crescent in evening twilight the night
of Saturday the 25th. By the following night, the sight will be
vastly better, and then the whole waxing affair becomes totally
obvious. Be sure to look for earthlight (light reflected from Earth) on the
nighttime side of the Moon, allowing you to see the whole lunar
disk. As the lunar phase grows, someone on the Moon would see a
waning Earth, and earthlight fades away.
The night of Sunday the 26th, the Moon will lie in a wonderful
position just above the Pleiades star cluster, both of them in
turn lying just above the planet Mercury, which is making
fine showing this week, as it passes greatest eastern elongation
with respect to the Sun the previous night.
The following evening, that of Monday the 27th, the Moon will have
moved to a higher position between the Taurus's Hyades and
(farther up) the star Elnath (Beta
The end of the week sees another "cross quarter day," this one
around April 30-May 1 (May Day), when we are halfway between the
beginning of spring and the start of summer. With the Sun halfway
between the vernal equinox and
the summer solstice, the crescent
will be heading toward its first quarter position in southwestern
The evening also brings us Saturn. Idling
in southeastern Leo, Saturn crosses
the meridian to the south just after
the end of formal twilight around 9:45 PM Daylight Time, which is
about the time Mercury sets. The ringed planet is then with us
nearly all night, setting about the time Venus rises in the
east, near the beginning of morning twilight, 4:30 or so AM. By
that time, Jupiter is well
up in the southeast in a setting among the faint stars of
In late evening, then cast your eyes nearly overhead (for the
temperate northern hemisphere) to admire Ursa Major's Big
Dipper. To the south toward Leo and Cancer, you'll
find three pairs of stars that the ancient Arabs saw as the "leaps" of the gazelle.