Photo of the Week.. Early in the year, Jupiter
passed by Aries, the constellation up and to the right.
Astronomy news for the week starting Friday, August 24, 2012.
We start as usual with the encircling Moon, which has been with us
almost since the Earth was born. It seems to have been formed by
a giant collision between primitive Earth and a competing Mars-
sized body, the debris forming our remarkable natural satellite.
After passing first quarter on Friday,
August 24, the Moon spends the entire week waxing in its gibbous phase. That ends on the morning of
Friday the 31st with full Moon after
Moonset in North America. The night of Thursday the 30th, the Moon
(the "grain Moon") will rise just south of east near the "Water Jar" of Aquarius (the stars washed out by Moonlight) a bit shy
of exact fullness. As the second one in a month, this full Moon
is by obscure tradition called a "blue Moon," which has nothing to
do with its actual color. The only planetary passages involve the
two outer planets (if we may still call Pluto a
"planet"). On Sunday the 26th, the Moon invisibly encounters
Pluto, while on the night of Thursday the 30th, it drifts north of
Neptune, now
considered the outermost real planet (Pluto one of the chief bodies
of the tattered Kuiper Belt, which contains the reservoir of the
short period comets).
The early evening planetary show in the west is pretty much over.
The Saturn/Spica pair sets just half an hour
after the end of twilight, and requires a flat horizon, and
probably binoculars, to see. Mars, to the
east of them, goes down shortly thereafter. The real Mars show
lies with the successful Curiosity rover, which is
beginning to send back some spectacular images.
Now well-separated from Venus, Jupiter makes a
transition by rising at midnight (Daylight Time) still to the
northeast of Taurus's Hyades (which with orange Aldebaran makes the head of the
celestial Bull). Brilliant Venus then rises around 3 AM more or
less to the south of Gemini's Castor and Pollux. Close to the morning
horizon, at then end of the week
Mercury encounters Regulus in
bright dawn.
For those in temperate northern latitudes, the bright star Vega is flying practically overhead in
early evening. It is one of a trio of northern luminaries, the
others Arcturus (now seen in the
west as twilight darkens the sky) and winter's Capella, which later on at night
will be seen rising in the northeast. Just barely dimmer than
Arcturus, Vega is the fifth brightest star in the sky (the three
brightest being Sirius, Canopus, and Alpha Centauri, all of which are in the southern celestial hemisphere).
