Photo of the Week.. Mountains anchor an immense sky.
Astronomy news for the week starting Friday, July 20, 2012.
Having passed its new phase on the night of Wednesday, July 18, the
Moon spends the nearly entire week in its waxing crescent phase, not reaching first quarter until the morning of Thursday, July 26,
when you get to see the perfect phase. Nicely visible in western
twilight the evening of Friday the 20th, by the morning of Friday
the 27th, it will have just barely entered the waxing gibbous. We'll then have
lovely sights the evenings of Monday the 23rd through Wednesday the
25th, as the growing crescent takes on
Mars and Saturn. On Monday
evening, the Moon, Mars, and Saturn will make a ragged line, the
Moon below and to the right, with the star Spica down and to the left of Saturn.
The following night the Moon will be seen several degrees below
Mars, while on Wednesday, we will see Saturn, Spica, and the Moon
making a fine open triangle. The Moon actually occults, or covers,
Spica on Wednesday the 25th, but only as seen from
Antarctica.
The planetary scene changes, but slowly. We are graced with two
planetary pairings,
Jupiter and Venus in the
eastern morning sky, Mars and Saturn in the western evening sky.
Take the latter first. Both moving easterly against the stars,
Mars, to the west of the ringed planet (Mars, Saturn, and Spica
making a long triangle), is making more and more of an impact on
the Saturn/Spica scene. With Mars fading as the Earth pulls away
from it, Saturn is marginally the brightest of the three. Mars
disappears over the horizon around 11:30 PM Daylight time, Saturn
just half an hour later.
Morning gives us by far the better sight, with Jupiter and Venus
more or less bracketing the Hyades of Taurus
along with orange Aldebaran.
Jupiter rises at 2 AM, about an hour ahead of much brighter Venus,
both now well in advance of twilight. With Jupiter on top, the
pair climbs the morning sky until it fades away in dawn. Morning
twilight begins about 4 AM, so look early. If you do, you might
also see some meteors from the Delta Aquarid shower, which peaks early next week.
High in the sky and nearly overhead in late evening look for the
pair of boxes that make up most of Hercules, the great Hero of the ancient past. The more
northerly of the two is a well-known asterism called (for its
obvious shape) the "Keystone." To
the southwest of it is the semicircle of stars that makes up Corona Borealis, the Northern Crown,
to the east the bright star Vega in
Lyra. Hercules lies atop a great
stack of constellations that
extends through Ophiuchus and
Serpens to the south, with Scorpius far below.
