We begin the week on Friday the 13th with the last quarter Moon,
and then will watch it wane in the crescent phase toward new, which is not reached
until Skylights' next week, on Saturday the 21st. Watch in the
morning hours as the Moon gets ever closer to the eastern dawn
horizon, the Earthlight on the
lunar nighttime side getting ever stronger until the thin crescent
just disappears into twilight. The morning of Monday the 16th, the
crescent will appear just above Saturn. Our lunar companion then
takes a ride through southern Leo,
appearing down and to the left of Leo's luminary, Regulus, the morning of Tuesday the
17th.
Saturn is the only one of the bright planets we have left to
admire, and you have either to stay up late or get up early to see
it. If you do, the planet, rising around 2 AM daylight time,
precedes the rising of Regulus. By the onset of dawn, they make a
fine couple in the eastern sky, Saturn (above Regulus) the brighter
of the two. Even though Mercury passes its
greatest eastern elongation with the Sun on Monday the 16th,
the low angle of the evening ecliptic against the horizon renders
the little planet -- though bright -- very difficult to see. Mars
(still to the east of the Sun) and
Venus (still to the west of the Sun) are completely (and
respectively) lost to evening and morning twilights.
Jupiter, while still visible, is a tough find in evening, as it
sets before twilight ends. That leaves the evening sky with
Uranus and Neptune, which
take accurate maps and positions to locate in their respective
current constellations, Aquarius
and Capricornus (Uranus actually
visible to the naked eye in a dark sky).
The fading Moon allows a wonderful opportunity to see the Orionid
meteor shower, whose meteors appear to emanate from the celestial Hunter. Though the broad
peak runs from the morning of Friday the 20th through Sunday the
22nd, the shower will be building during much of the current week
(and actually runs through most of October and into November), so
take a look. Under a dark sky, at maximum you may see 20-25
meteors a minute. They are caused by the debris of Halley's
Comet hitting the Earth's atmosphere. Halley's flakings come
at us twice, and will hit us again next spring as May's Eta Aquarids.
No matter what the time of year, northerners can always admire
circumpolar Ursa Minor and its
Little Dipper, whose handle ends in Polaris, the second magnitude Pole Star, which sits close to the
sky's northern apparent rotation pole
(and guides the way north, its angle above the horizon even
providing us with our latitude). The southern analogue is not so
easy to see. Surrounding the southern celestial pole, invisible to
anyone north of the equator, lies much fainter (fifth magnitude)
Sigma Octantis in the modern (and very dim) constellation Octans, the Octant, the dichotomy an
accident of nature.
