Photo of the Week.Made by moonlight refracting
through high ice crystal clouds, a striking 22-degree halo with an upper
tangential arc surrounds the Moon.
Astronomy news for the week starting Friday, June 19, 2009.
Skylights now resumes its normal weekly schedule.
The week begins with the Moon in a thin waning
crescent phase nicely visible to the east-northeast in morning
twilight as it heads towards new on Monday the 22nd. The morning
of Saturday, June 20, the crescent will make a pretty sight with
the Pleiades, the cluster
lying down and to the left of the Moon. The last sight of the Moon
will be the morning of Sunday the 21st, when the very thin crescent
will be seen up and to the left of Mercury, which is making
its best appearance for this round (though not a very good one, the
planet hard to spot).
Then we flip past new Moon into evening skies and the waxing crescent, which first becomes visible
in western twilight the evening of Tuesday the 23rd. The night of
Thursday the 26th, look for the Moon, Regulus (in Leo), and
Saturn to be all in a line stretching up and to the left of the
Moon along the ecliptic, the
apparent path of the Sun. Less
than a day after new, the Moon passes perigee,
where it is farthest from Earth, the
coincidence with the phase bringing especially high tides to the
coasts.
The biggest news for the week involves the Earth and Sun, as the Sun will
pass the Summer Solstice in
classical Gemini the night of
Saturday the 20th, or the morning of Sunday the 21st, depending on
just where you live. Astronomical summer then begins at 1:46 AM Eastern Daylight Time or
12:46 CDT on the 21st. But farther west, its 11:46 MDT, 10:46 PDT,
on the 20th (subtract another hour for Alaska, three hours for
Hawaii). On these two days, the Sun will rise as far northeast as
possible and similarly set in the far northwest. Overhead at the
Tropic of Cancer, it will be as high at noon in temperate zones as
possible as well.
Rising ever earlier, Jupiter now
comes up in the southeast around 11:30 PM Daylight Time, and
crosses the meridian to the south in morning twilight just before
sunrise. By that time, brilliant Venus will be
well up, having risen around 3 AM, before dawn begins to light the
sky. At the same time, look for much fainter
Mars, which rises with Venus. Back into the evening, Saturn,
still to the east of Regulus, is becoming strictly an evening
object, setting just after midnight. At the same time, look for
much fainter Mars, which rises with Venus. In lesser planetary
news, Pluto begins
retrograde motion (which, given Pluto's distance, does not
amount to much) on Tuesday the 23rd.
It's Arcturus season, the bright
orange star of Bootes, the
Herdsman, passing high to the south around 9 PM. Then as Arcturus
moves to the west, we watch a parade of constellations that include
the semi-circle of Corona Borealis
(the Northern Crown), dim Hercules,
then bright Vega in Lyra (the Harp) and Deneb in Cygnus, the Swan, the star also marking the top of the
Northern Cross.
