Photo of the Week. AS fogbow, or white rainbow,
caused by the diffraction of light, the bending of sunlight
through fine droplets, which makes the rainbow colors smear
together and come out white. But here not completely: note the
slight reddish tinge at the upper edge.
Astronomy news for the week starting Friday, October 8, 2010.
The Moon, having gone through its new phase
on Thursday, October 7, arises in its waxing crescent,
first seen the evening of Friday the 8th as an ultrathin sliver in
bright twilight. It's better-seen the following night, when it
splits the difference between Mars and Venus, the red one above,
the bright one below, though the two planets are, if anything, now
hard to see. The crescent then grows, approaching first quarter,
that phase reached on Thursday the 14th, after which it enters the
waxing gibbous phase. Low in the sky, the
waxing crescent swings through Scorpius (to the right of Antares the evening of Sunday the
10th, to the other side the following night), then past Sagittarius, finally winding up at
first quarter between the classical figures of the Archer and Capricornus.
Though Venus and Mars are still technically
there, they are nearly invisible in western twilight. As they set
early, the western evening sky is finally pretty much bereft of the
planets it once so gloriously held. So instead as twilight ends,
look east to bright Jupiter. The giant of the planetary system, 11 times
the diameter of Earth, crosses the meridian to the south ever-earlier, now
around 11:30 PM Daylight Time, setting as dawn begins to light the
morning sky. Still gracing western
Pisces to the southeast of the Fishes' "Circlet," Jupiter lies just barely north of the Aquarius-Pisces border about four
degrees southwest of the Vernal Equinox. To the northeast of
Jupiter, with binoculars you might spot Uranus, which has been hanging out with its much brighter
planetary companion for some time now.
Much farther east, as the week begins, Mercury and Saturn invisibly rise together in growing dawn. But then
they quickly split apart, Mercury descending toward conjunction
with the Sun next week, Saturn slowly climbing
out of the morning murk. By the end of the month, it will have
cleared the horizon before dawn commences, launching itself into
yet another round of visibility.
With the Dipper descending the
evening's northwestern sky, Cassiopeia's "W" is making its entrance in the
northeast, with the graceful curves of Andromeda to the south of it. With the sky now dark,
you might spot the north-south squiggle of stars that makes the
obscure modern constellation Lacerta, the Lizard, which lies between the celestial
Queen and Cygnus's tail, great Deneb. At the Swan's other end,
southwest of Albireo (which marks
the Swan's head) lies the vastly fainter "W" that makes part of
modern Vulpecula, the Fox.