October Skies 2006

October marks the first full month of Autumn (Fall).  The Autumn season started in late-September and ushers in 6 months of the Sun’s path in the sky being located South of the Celestial Equator. What this means for us is the Sun will be rising South of East and will set South of West until the 1st day of Spring. Our nights will last longer than our days until then.

Many of Summer’s spectacular stars and constellations remain visible most of the night during October, while some prominent Winter sky sights also become good observing targets.  The still visible parts of the summer and winter Milky Way present excellent opportunities for viewing in binoculars and small telescopes.

The Sun begins October in the large zodiac constellation VIRGO and remains there nearly all month. It will enter the next zodiac constellation to the East, LIBRA, on October 30th.

The Moon:
The Moon is approaching Full when October begins. This month’s FULL MOON occurs the evening of the 6th in PISCES, when the Full Moon will rise exactly at sunset.
The 3rd QUARTER Moon occurs on October 13th in GEMINI.
October’s NEW MOON occurs the morning of the 22nd in Virgo.
The 1st QUARTER MOON is seen on October 29th in CAPRICORNUS.

The Moon may be seen to pass near three naked-eye planets in October:
MERCURY & JUPITER: Binoculars are a must to see this Moon + 2-planet conjunction!  Look South of West and VERY low to the horizon about 6p.m. the evening of October 23rd. Jupiter will appear as a bright star. Mercury, much fainter, is below (closer to the horizon) and slightly to the left (South) of Jupiter.  The Moon is closer yet to the horizon directly below Jupiter.

SATURN: The Moon appears close to Saturn in LEO before dawn the morning of the 16th.

The Moon is also to be seen near these prominent stars during October:
The Waning Gibbous Moon passes directly through the Pleiades star cluster between 8:20p.m. (moonrise) and midnight the evening of the 9th .
The 3rd Quarter Moon rides high near Pollux in Gemini the morning of October 14th
The waning crescent Moon is near REGULUS in LEO the morning of the 17th.
The Waxing Crescent Moon is near Antares in SCORPIO the evenings of the 24th and 25th.

The Evening Sky:
The Sun: Sunset in Central Arizona on October 1st occurs about 6:05p.m..  As winter approaches, we should notice our Autumn evenings lengthening and our sunsets occurring a bit earlier each day.  By month-end the Sun sets at 5:30p.m.

Evening Planets.  Mercury, Mars, and Jupiter:
Essentially, there are no Evening Planets this month!  Mercury, Mars & Jupiter are all nearly behind the Sun and may be difficult or impossible to spot. Mercury & Jupiter might be glimpsed very low near the horizon shortly after sunset. Mars will be lost in the Sun’s glare all month.

Mercury starts the month in Virgo and moves into Libra on October 8th, where it remains the rest of the month. Mercury is never visible in a fully dark sky, so will be difficult to observe.  However, binocular observers may glimpse the planet low in the Southwest after sunset. Early in the month Mercury moves toward Jupiter and they then remain close the rest of the month.

Jupiter is easily spotted in early October low in the West after sunset. However, it will be lost in the sun’s glare by month end. Jupiter will continue to approach the Sun enroute to passing it and moving into the morning sky in November.

Observers with binoculars and a clear view to the horizon should begin to look for Jupiter (highest), Mercury, and the 2-day-old Moon below Jupiter on October 23rd about 20 minutes after sunset. That evening the Moon, Mercury & Jupiter respectively set 40 minutes, 60 minutes and 70 minutes after sunset.

Venus, the brightest object in the night sky after the Moon, is nearly in line with – and on the far side of – the Sun.  By the end of October Venus moves past the Sun and into the evening sky. However, it will not be far enough from the Sun to be seen as our “Evening Star” until late-December or early January. Since it is on the opposite side of the Sun from the Earth, brilliant white Venus would appear through a telescope in its “Full” phase.

As the Moon passes through Capricornus, Aquarius, Aries, Taurus & Gemini in early October, it will occult (pass in front of) several naked-eye stars.  See the complete list (with disappearance and reappearance times) here. Use binoculars or a small telescope for best viewing.

The Morning Sky:
Early October sunrises are shortly after 6:25a.m. but month-end sunrise occurs nearly half an hour later at 6:50a.m.

Morning Planets:  Venus, Mars, Saturn.
Venus is too close to the Sun to be visible at all in October and will shortly become an Evening Planet. Venus will not become a morning planet again until late-August/early-September 2007.

Mars is also too close to the Sun to observe in October. Late in October, Mars enters the morning sky, but it will not be visible in a dark morning sky until February 2007.

Saturn, the brightest object in the eastern sky, is seen in LEO the Zodiac lion.  The ringed planet rises about 2:55a.m. on the 1st but about two hours earlier on the 31st.  On the 16th the waning crescent Moon stands about 3-degrees north (left) of Saturn.

What Else to See?
As the Moon passes through Capricornus, Aquarius, Aries, Taurus & Gemini in early October, it will occult (pass in front of) several naked-eye stars.  See the complete list (with disappearance and reappearance times) here.

Binoculars or a small telescope will help morning observers sight interesting WINTER Milky Way objects in October. Many such objects are already high in the sky by midnight. They include the Pleiades star cluster, the star-rich Winter Milky Way Constellations of CASSIOPEIA, PERSEUS, (including the famous “Double Cluster” midway between Perseus and Cassiopeia), AURIGA and GEMINI.  Look for Cassiopeia and Perseus low in the East at 8:p.m. on October 1st, while Auriga rises by 10:30p.m. and Gemini by 12:30a.m. (and earlier each day throughout the month).  However, the Moon will complicate the picture this year, preventing dark-sky observing of faint Milky Way objects during much of the month.

Evening observers can avoid bright moonlight by skygazing between the 10th and the 27th.
Morning skywatchers should try to observe between the 1st and 5th (when the Moon is in the Western sky) then again after the 16th, when the Moon will be a thin crescent.

Good Luck Observing!