Astronomy news for the week starting Friday, November 9, 2007.
Comet
Holmes just continues to get better
and better. Find it in Perseus
at bright third magnitude still just to the east of Mirfak, Alpha Persei, which it is
slowly approaching. The comet has developed a short complex tail (visible
only telescopically). Short, at least from our perspective, as
Holmes is so close to
opposition to the Sun (reached November 29th) that the tail
projects more or less away from us and is severely foreshortened.
At of the start of the week, the comet was 2.5 Astronomical Units
(Earth-Sun distances) from the Sun and 1.6 from Earth (closest
approach having taken place November 6). Look in the northeast in early
to mid evening.
The rest of the week begins, Friday November 9, with the Moon
passing through its new phase, from
which, during the week, it will slowly climb through waxing crescent. It will not reach first quarter until next week, on Saturday
the 17th. Look in twilight the evening of Monday the 12th to see
the very thin crescent down and to the left of
Jupiter. The following evening, the pair will be more or less
on a line parallel to the horizon, the Moon still to the left.
Jupiter, the giant of the Solar System
(excepting of course the Sun) is
rapidly disappearing into twilight, setting just after the sky gets
fully dark, so this is probably your last chance to catch it.
Farther east, the planetary sky becomes dominated by Mars, which
now rises in central Gemini
around 8 PM, just about the same time as does Betelgeuse in Orion. Surrounded by bright stars,
the planet passes a milestone, as it begins
retrograde (westerly) motion on Thursday the 15th, as it heads
towards its opposition on December 24.
Moving yet farther to the east, Saturn, in Leo to the east of Regulus, climbs above the horizon
about half an hour past midnight. The small star to the southwest
of it is Rho Leonis. Then wait
a bit until brilliant Venus, more than
100 times brighter than Saturn, rises shortly before 3 AM, just
before Mars crosses the meridian about
as high for mid-northerners as they will ever see it. Mercury is also
still on display, the little planet rising just as dawn
begins.
Small stuff makes a bit more news too, as Ceres, the largest (and first-discovered) asteroid,
passes opposition with the Sun on Friday the 9th in Cetus, just south of Aries, while Juno
(number three on the discovery list) passes conjunction with
the Sun on Wednesday the 14th.
It's a fine time of year for three of the sky's best-known
asterisms (informal patterns). Around 8 PM look high in the sky to
see the Great Square of Pegasus, south of which is the Circlet of Pisces. Then look to the
west of the Circlet for the Y-shaped Water Jar of Aquarius, Pisces, Aquarius, and Capricornus (farther west) part of the sky's "wet
quarter." To the southeast of the Circlet is the Vernal Equinox, which the Sun passes
on the first day of spring.
