SEPTEMBER 2012 NIGHT SKY CALENDAR

SEPTEMBER 2012 NIGHT SKY CALENDAR

THURSDAY, SEPTEMBER 6

 MOON 4.2 DEGREES SOUTH OF PLEIADES

What?  Almost an entire week into September until one encounters a noteworty event?   Well, yes, actually.   Of course, just as a few dim stars are actually closer to the North Celestial Pole than Polaris, quite a few celestial events occurred in September before the 6th, but they lacked the prominence that would have otherwise compelled us to include them.    That we splattered coffee over the top of the almanac page is entirely incidental.

The Pleiades is a galactic, or open, star cluster within Taurus the Bull.    When observed with the unaided eye, it appear cloud-like, containing 6-7 resolvable stars.  When viewed telescopically, one can discern more than a hundred members.        Tonight, the waning gibbous moon appears 4.2 degrees south of it.   While the lunar light interference might impair one's ability to clearly observe the cluster, it will still remain visible.    

[THURSDAY, SEPTEMBER 6: STONE CIRCLE SOCIETY MEETING   7:00 p.m.]

FRIDAY, SEPTEMBER 7

MOON 0.70 DEGREES SSW OF JUPITER

This event teaches us that celestial events are not created equal.      One observer's appulse (the apparent closest approach of two bodies) is another person's occultation (the passage of one celestial body behind another.)   A lunar occultation of a planet is not exactly rare, because the planets, like the Moon, reside along the ecliptic, the Sun's apparent annual path.   However, the occultation alignment is so precise that such occultations are visible within narrow regions.  While we will see the Moon and Jupiter within less than a degree of each other, some Central American observers will see the Moon occult Jupiter.    Occultations are splendid events because the occulted body winks out instantly against the Moon's air-less limb.  Were the Moon covered in an atmosphere, the blocked body's disappearance would be gradual.

LAST QUARTER MOON.

MONDAY, SEPTEMBER 10

MERCURY AT SUPERIOR CONJUNCTION

Do you know what we love about planets?   They keep moving in the same direction without hindrance and direction change.     As they move, their positions relative to each other constantly change.  Today, Mercury moves on the Sun's far side relative to Earth.  It's true that Mercury is not visible in this configuration, but we can at least know the first world's location thanks to the witchcraft we call 'mathematical astronomy.'  So, even though we won't see Mercury tonight, we'll know where it lurks.

Remember: a planet in superior conjunction will then proceed to the eastern early morning sky.   A planet in inferior conjunction (when it passes between Earth and the Sun) re-emerges into the western early evening sky.  Only Mercury and Venus can ever be at inferior conjunction.

WEDNESDAY, SEPTEMBER 12

[MIDNIGHT METAPHYSICAL SOCIETY MEETING:    7:00 p.m.]

THE MOON 3.6 DEGREES SOUTH OF VENUS AND 6.0 DEGREES SOUTH OF THE BEEHIVE STAR CLUSTER

Sometimes events involve more than two celestial objects.  Tonight, we'll see the Moon, Venus and the Beehive Star Cluster together.     This diverse trio includes a moon, a planet and a galactic star cluster.   Though only a crescent, the Moon will be the most prominent of the three objects.   Venus appears as a bright dot, though it would reveal itself to be a crescent, as well, if observed telescopically.     The Beehive Star Cluster is the most diffuse of the three.      That these distant objects appear so close is illusory.   The moon is approximately a quarter of a million miles from us; Venus is tens of millions of miles distant; and the Praesepe Cluster is hundreds of trillions of miles away.    On a rough distance scale model, the Moon is one-quarter of an inch away; Venus is two feet away**; and the cluster is 54,000 miles distant. 

THURSDAY, SEPTEMBER 13

VENUS 2.3 DEGREES SOUTH OF THE BEEHIVE CLUSTER

The Moon moves approximately 12 degrees a day, so it will be quite displaced from the Moon and the Beehive

Cluster, thereby providing you with the opportunity to admire the planet and cluster by themselves.  The cluster will be easier to see tonight than it was last night.

SATURDAY, SEPTEMBER 15

NEW MOON.

The technical term for new moon is "conjunction," as it will be in conjunction with the Sun.

SUNDAY, SEPTEMBER 16

SUN ENTERS VIRGO THE MAIDEN

The Sun passes through thirteen constellations throughout the year.    This progression occurs because Earth revolves around the Sun and makes the latter appear to move through these star patterns.   The amount of time the Sun occupies each "house" varies considerably.   Sol spends more time in Virgo than in any other single constellation.  The Sun moves into Virgo around mid September and leaves at the end of October.  

TUESDAY, SEPTEMBER 18

MOON 4.8 DEGREES SSW OF SATURN

One might complain that we devote too much time to the Moon in these sky calendars.  Ours is a big Universe rife with objects, and the people often dismiss the Moon as an insignificant part of it.  Well, negligible though it might be in the cosmic scheme, the Moon is also the closest celestial object and therefore is also one of the brightest and fastest moving.    It attracts our attention frequently and quite often veers close to the planets.

Tonight, for instance, one can see the Moon and Saturn together in the western evening sky.    

[TUESDAY, SEPTEMBER 18:  STAR DOME ASTRONOMY: An introductory astronomy course  BEGINS.]

WEDNESDAY, SEPTEMBER 19

MOON 0.83 DEGREES ESE OF MARS

And, here we are again sighting the Moon and a planetary companion.   Saturn is slightly brighter than Mars, but the fourth sphere is a bit higher in the sky.       You can use the Moon this week to find Mars and Saturn, two of the three naked eye superior planets. (A superior planet is one that is farther from the Sun than Earth.)

SATURDAY, SEPTEMBER 22:

AUTUMNAL EQUINOX  (10:47 a.m. EDT)

Astronomical autumn begins in the northern hemisphere.    Astronomical spring begins in the southern hemisphere.   Each year we drone on about how the Sun intersects the celestial equator and that, in theory, the day and night lengths are equal on this day. (They aren't.)   Occasionally, we propagate the notion that only on the equinoxes can one balance eggs on their ends, when in fact one could balance an egg on any day if one had vast stores of patience and a forgiving social calendar.   

We know that fall begins and for some, this information alone is sufficient.

SATURDAY, SEPTEMBER 22:

FIRST QUARTER MOON

SATURDAY, SEPTEMBER 29

URANUS AT OPPOSITION

This year we've decided not to always neglect the "invisible worlds," defined as those planets that are only observable telescopically.  While Uranus can be seen with the unaided eye, provided you have a dark sky, precisely know its position, and have the kind of eyesight that enables you peer through winter clothing,  the seventh sphere is not considered a naked eye planet.       Uranus rises when the Sun sets and sets around sunrise tonight.  So, if you at least want to know where to look as you attempt to find Uranus, you can observe the eastern sky in the evening and the western sky in the morning.   Look along the meridian (the line connecting North and South) around midnight. 

SATURDAY, SEPTEMBER 29

FULL MOON  (PICK EVENT!)

We chose the Harvest Moon as the Moon's pick event.      Tha Harvest Moon is NOT defined as September's full moon, but is, instead, the full moon closest to the Autumnal Equinox.   So, one can have the harvest moon in October now and again.     The Harvest Moon is so named because it is the full moon that lights the field during the harvest.   Contrary to popular legend, the Harvest Moon is not necessarily the year's brightest full moon. All full moons are bright enough to illiuminate the night landscape enough to render most features visible.   

PLANET WATCH

MERCURY:  September 2012 is not a stellar month for Mercury.  (More praise.  That line required four weeks.) Mercury is backstage most of the month, appearing in the early western dusk sky by month's end.  Mercury is also behind the Sun (superior conjunction) on September 10th.  VERDICT:    Oh, if you feel a furious compulsion to see Mercury, try soon after sunset at month's end.  Otherwise, don't bother this month.

VENUS: (PICK PLANET)    Venus is spoiled rotten.    It gets the pick planet diadem at least four times a year, if not more.  However, being so bright and beautiful entitles it to such a conveted distinction. Venus is a gorgeous and brillant planet in the early morning sky.    VERDICT:  Of course it's worth your time to seek out the pick planet.  One drawback is timing:   Venus is only visible in the early morning eastern sky. 

MARS:    Mars and Saturn are western evening sky planets.    While Saturn will vanish next month (see Saturn section of Planet Watch), Mars remains visible for the rest of the year.   Though the faintest of the visible planets, Mars is still a moderately bright world and its reddish hue makes it distinct.  VERDICT:  Not a difficult sight principally because of its crimson color.    Find it in the western evening sky tonight.

JUPITER:   Venus is sitting pretty now, but later this autumn Jupiter will become the pick planet.  At month's beginning it rises around midnight, but is rising just before 10:00 p.m. by the end of September.     The king planet grows brighter throughout the rest of 2012 and rises ever earlier.  VERDICT: a planet best found by those who prefer late night viewing, so if you're up after midnight, take a peek at Jupiter.     Otherwise, wait a few weeks until it rises at a more convenient time and becomes all the more brilliant.

SATURN:   While Mercury, Venus, Mars and Jupiter will all be visible next month, Saturn will take a powder in October.    This month, the Lord of the Rings orb is low in the western evening sky, and will steadily approach the setting Sun throughout the month.  VERDICT:   Try for Saturn early in the month and give it a miss by month's end.  Though it vanishes in October, Saturn will return to the eastern pre-dawn sky in November.

*"Noteworthy" is one of those dangerous words.    One person's 'noteworthy' is another person's 'unimportant,' and another person's 'essential,' and yet another person's  'you included that?  Really?'     We realize that we cannot possibly include every event to please every person.     Were we to even attempt that, the sky calendars would be phone-directory thick and twice as confusing.   (By the way, in this cell phone age, that 'phone directory thick' analogy is an epic fail.)

**All these distances are variable within a certain range.