September Calendar by Dave Mitsky

All times, unless otherwise noted, are UT (subtract 4 hours and, when appropriate, 1 calendar day for EDT)

9/1 A double Galilean satellite shadow transit begins at 00:22; the Moon is 0.54 degree south-southwest of the first magnitude star Antares at 1:00; Mercury is in superior conjunction with the Sun at 5:00; the equation of time equals zero (clocks and sundials are in agreement) at 15:00
9/2 Maximum lunar libration of 10.1 degrees occurs at 2:00; asteroid 3 Juno is in conjunction with the Sun at 6:00; a double shadow transit begins at 17:10
9/4 A double shadow transit begins at 13:40; Pluto is stationary in longitude at 19:00
9/5 Pluto is stationary in right ascension, with direct (eastward) motion to resume, at 4:00
9/5 Uranus (magnitude 5.7, angular size 3.7”) is at opposition at 11:00; Neptune is 3 degrees north of the Moon at 22:00; Venus is 0.8 degree north of the first magnitude star Regulus at 23:00
9/6 Venus is 0.73 degree north-northeast of Regulus at 3:00; Venus is at perihelion at 10:00
9/7 Uranus is 0.46 degree west-northwest of the Moon at 16:00; the Full Moon (known as the Barley, Corn or Fruit Moon and the largest of 2006) occurs at 18:42 - a small (19%) partial lunar eclipse will be visible from Africa, most of Asia, Australia, and eastern Europe, with maximum eclipse taking place at 18:51
9/8 The Moon is at perigee, subtending 33’27” from a distance of 357,175 kilometers, at 3:00 - unusually high tides will occur; minimum lunar libration of 0.6 degree occurs at 6:00; the Moon is at the ascending node (longitude 355.4 degrees) at 11:05
9/9 The north pole of the Sun is most inclined (7.25 degrees) towards the Earth today; a double shadow transit begins at 20:33
9/10 Mars enters the southern hemisphere sky at 20:00
9/11 Asteroid 4 Vesta is in conjunction with the Sun at 1:00; a double shadow transit begins at 16:18
9/12 The Moon is 0.78 degree north of the center of the bright open cluster M45 (the Pleiades) in Taurus at 22:00
9/14 Last Quarter Moon occurs at 11:15; maximum lunar libration of 10.4 degrees occurs at 15:00
9/15 Asteroid 68 Leto is at opposition at 2:00; a double shadow transit begins at 5:37; the Moon is at declination of 28.72 degrees north, its northernmost position until 2025, at 17:00; Mercury (magnitude -0.6) is 0.16 degree south of Mars (magnitude 1.7) at 20:00
9/16 The Moon is 2.0 degrees south of the first magnitude star Pollux at 23:00
9/17 The Sun enters the constellation of Virgo (ecliptic longitude 173.98 degrees) at 0:00
9/18 The Moon is 2.0 degrees north-northeast of the bright open cluster M44 (the Beehive) in Cancer at 3:00; the theoretical middle of the eclipse season (the Sun is at the same longitude - 175.2 degrees - as the Moon’s descending node) occurs at 6:00; a double shadow transit begins at 16:54
9/19 Saturn is 2.2 degrees south-southwest of the Moon at 4:00
9/20 The Moon is 1.8 degrees north-northeast of Regulus at 0:00; Mercury is at the descending node at 13:00
9/21 The Moon is 1.8 degrees north-northeast of asteroid 3 Juno at 13:00; Venus is 0.85 degree north-northeast of the Moon at 15:00
9/22 The Moon is at the descending node (longitude 175.4 degrees) at 3:42; the Moon is at apogee, subtending 29'24" from a distance of 406,500 km, at 5:00; New Moon (lunation 1036) occurs at 11:45 - a partial solar eclipse is visible from most of South America (an annular eclipse occurs in parts of Guyana, Surinam, and French Guiana), portions of Antarctica, and southern and western Africa
9/23 The autumnal equinox occurs at 4:06; the Moon is 2.0 degrees south-southwest of Mars at 9:00
9/24 Mercury is 1.6 degrees north-northeast of the Moon at 2:00; the Moon is 0.51 degree south of the first magnitude star Spica at 14:00
9/26 Jupiter is 5.0 degrees north-northwest of the Moon at 13:00
9/28 Mercury is 1.1 degrees north-northeast of Spica at 0:00; the Moon is 0.57 degree southwest of Antares at 8:00; Venus is at its greatest latitude north of the plane of the ecliptic (3.4 degrees) at 9:00
9/30 First Quarter Moon occurs at 11:04; Mercury is aphelion at 22:00

During September the zodiacal light, or false dawn, can be seen about two hours before the sun rises.

The Alpha Aurigids, a minor meteor shower with a rate of only 7 per hour, peak on the morning of September 1.

The Moon is at its greatest northern declination on September 15 and its greatest southern declination on September 2 and 29. Times and dates for the lunar light rays predicted to occur this month are available at http://www.lunar-occultations.com/rlo/rays/rays.htm

The planets on September 1: Mercury (-1.8 magnitude, 4.9", 100% illuminated, Leo), Venus (-3.7 magnitude, 10.1", 97% illuminated, Leo), Mars (1.8 magnitude, 3.6", 99% illuminated, Virgo), Jupiter (-1.9 magnitude, 34.3", 99% illuminated, Libra), Saturn (0.4 magnitude, 16.4", 100% illuminated, Leo), Uranus (5.7 magnitude, 3.7", 100% illuminated, Aquarius), Neptune (7.8 magnitude, 2.3", 100% illuminated, Capricornus), and Pluto (13.9 magnitude, 0.1", 100% illuminated, Serpens Cauda).

Mercury is not easily observable from the northern hemisphere this month.

With each passing day, Venus sinks farther into the morning twilight. It disappears from view by the end of the September.

Mars sets about 45 minutes after sunset. Soon after the middle of the month, the Red Planet is lost to northern observers until December.

Jupiter is low in the southwestern sky at twilight. The gas giant is 0.5 degree north of Alpha Librae (Zubenelgenubi) on September 11 and September 12. Click on http://skyandtelescope.com/observing...icle_107_1.asp to determine transits of the central meridian by the Great Red Spot. The best chances for northern observers to have a final look at the GRS until Jupiter reappears in the morning sky at the end of the year are on the evenings of September 2, 5, 7, 10, and 12. Data on the Galilean satellites is available at http://skytonight.com/observing/obje.../3307071.html#

During September, Saturn climbs through the eastern morning sky. The Ringed Planet travels eastwards towards Regulus and is a bit fainter than in recent years, since its rings are now tilted less than 15 degrees from being edge-on.

Uranus reaches opposition on September 5 and is visible to the unaided eye from dark sites. It's approximately 1.4 degrees east of Lambda Aquarii (magnitude 3.7) at the start of the month and ends the month only 0.5 degree away from this star.

Neptune is positioned slightly more than one degree north-northwest of Iota Capricornii (magnitude 4.3) this month.

Pluto is still fairly well placed in the southern sky in the early part of September. It lies approximately 0.75 degree to the southwest of Xi Serpentis (magnitude 3.5).

During September, the periodic comet 4P/Faye may brighten to ninth magnitude as it leaves Pisces and glides through the southern part of Aries. The recently recovered periodic comet 177P/2006 M3 (Barnard 2) travels through Draco this month.

Asteroid 6 Hebe (magnitude 8.5) moves southward through southwestern Capricornus this month. On the night of September 15, it passes between two seventh magnitude stars.

Eighty binary and multiple stars for September: 12 Aquarii, Struve 2809, Struve 2838 (Aquarius); Alpha Capricorni, Sigma Capricorni, Nu Capricorni, Beta Capricorni, Pi Capricorni, Rho Capricorni, Omicron Capricorni, h2973, h2975, Struve 2699, h2995, 24 Capricorni, Xi Capricorni, Epsilon Capricorni, 41 Capricorni, h3065 (Capricornus); Kappa Cephei, Struve 2751, Beta Cephei, Struve 2816, Struve 2819, Struve 2836, Otto Struve 451, Struve 2840, Struve 2873 (Cepheus); Otto Struve 394, 26 Cygni, h1470, h1471, Omicron Cygni, Struve 2657, 29 Cygni, 49 Cygni, 52 Cygni, 59 Cygni, 60 Cygni, 61 Cygni, Struve 2762 (Cygnus); Struve 2665, Struve 2673, Struve 2679, Kappa Delphini, Struve 2715, Struve 2718, Struve 2721, Struve 2722, Struve 2725 (in the same field as Gamma Delphini), Gamma Delphini, 13 Delphini, Struve 2730, 16 Delphini, Struve 2735, Struve 2736, Struve 2738 (Delphinus); 65 Draconis, Struve 2640 (Draco); Epsilon Equulei, Lambda Equulei, Struve 2765, Struve 2786, Struve 2793 (Equuleus); 1 Pegasi, Struve 2797, h1647, Struve 2804, Struve 3112, 3 Pegasi, 4 Pegasi, Kappa Pegasi, h947, Struve 2841, Struve 2848 (Pegasus); h1462, Struve 2653, Burnham 441, Struve 2655, Struve 2769 (Vulpecula)

Challenge binary star for September: 1 Delphini

Fifty deep-sky objects for September: M2, M72, M73, NGC 7009 (Aquarius); M30, NGC 6903, NGC 6907 (Capricornus); B150, B169, B170, IC 1396, NGC 6939, NGC 6946, NGC 6951, NGC 7023, NGC 7142, NGC 7160 (Cepheus); B145, B164, B168, B343, B361, Ba6, Be87, Cr 421, Do9, IC 1369, IC 1516, M29, M39, NGC 6866, NGC 6871, NGC 6888, NGC 6894, NGC 6910, NGC 6960, NGC 6992, NGC 7000, NGC 7008, NGC 7026, NGC 7027, NGC 7063, NGC 7086 (Cygnus); NGC 6891, NGC 6905, NGC 6934, NGC 7006 (Delphinus); NGC 7015 (Equuleus); M15 (Pegasus); NGC 6940 (Vulpecula)

Challenge deep-sky object for September: Abell 78 (Cygnus)

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