The Solar System in September 2014
Up to September 27 dates and times are NZST (UT +12 hours) unless otherwise specified. NZDT starts September 28. Rise and set times are for Wellington. They will vary by a few minutes elsewhere in NZ.
The Sun rises at 6.44 am and sets at 5.58 pm on September 1. On September 30 the times are 6.55 am NZDT and 7.27 pm NZDT respectively.
Phases of the Moon (times as shown by guide)
First quarter: September 2 at 11.11 pm (11:11 UT) Full moon: September 9 at 1.38 pm (01:38 UT) Last quarter September 16 at 2.05 pm (02:05 UT) New moon: September 24 at 6.14 pm (06:14 UT)
The Planets in September
Mercury has its best evening appearance of the year for southern hemisphere viewers this month. Mars and Saturn are also early evening objects
Jupiter rises further into the morning sky but Venus is too close to the Sun to observe.
PLANETS IN THE EVENING SKY. Best viewed as the sky darkens following sunset.
MERCURY is an evening object throughout September. It reaches its maximum elongation 26° east of the Sun on September 21. It will then set more than 2 hours after the Sun. With a magnitude 0.1 it will be readily visible fairly low to the west as the sky darkens especially later in the month. It will be the brightest star like object in that region of the sky.
On the 20th and 21st Mercury will be only 45 arc minutes from the Spica, magnitude 1.1 thus an obvious pair in the western sky. Mercury will be noticably brighter.
Mercury is in Virgo all month. It will be brightest early in September, on the 1st magnitude -0.2, when it sets about 100 minutes after the Sun. By the end of September the planet will be a little less bright, magnitude 0.4. It will still be setting over 2 hours later than the Sun.
On the 26th a very thin crescent moon will be 5.5° below and to the right of Mercury with Spica just over 3° left of the moon.
MARS remains an evening object setting just after midnight all month; when NZDT starts at the end of September the planet will set close to 1am.
Mars starts September in Libra. It moves across the narrow part of Scorpius between the 13th and 25th and then on into Ophiuchus. While in Scorpius, Mars will move through the head of the Scorpion passing just over half a degree from the 2.3 magnitude star delta Sco on the 18th. After entering Ophiuchus, Mars will move past Antares, being closest on the 28th when the two will be just over 3° apart. Planet and star will be almost identical in brightness, thus they will make a notable pair of reddish objects in the evening sky.
The Moon passes Mars twice in September. On the 1st the 38% lit moon will be some 5.5° from Mars (but much closer to Saturn). On the 29th the 24% lit moon will 8° from Mars, the next evening the two will be 9° apart with the moon 34% lit.
SATURN, like Mars remains an early evening object throughout September. But as Saturn's motion to the east is less than that of Mars, it will drop behind the red planet and steadily set earlier. On the 1st it will set about half an hour before Mars, by the 30th almost two hours earlier at about 11 pm NZDT. So the planet is best viewed early evening as the sky darkens.
Saturn is in Libra during September. The moon joins Saturn on September 28, with the 15.7% moon 2° to the right of Saturn. Earlier, at about 5 pm NZDT, the moon will Occult Saturn, an event visible from Hawaii and the western parts of Alaska.
By the end of September the two asteroids Ceres and Vesta will be close to Saturn. In fact Vesta is closest to Saturn on the 14th, with the asteroid, magnitude 7.8, just over a degree to the right of, and slightly lower then Saturn. On the 30th Ceres, magnitude 9.0, will be 1.5° below Saturn.
Planets in the Morning Sky.
JUPITER rises a little over an hour before the Sun on September 1, 2 hours before it on the 30th. So, unlike Venus it will become more visible in the morning sky as the month progresses. Jupiter is in Cancer all month; on the mornings of the 20th and 21st the crescent moon will be a few degrees from the planet.
The equatorial plane of Jupiter is now nearly edge on to the Earth. The four major satellites of Jupiter orbit close to the plane of Jupiter's equator. As a result eclipses, transits and occultations of Callisto, as well as the other three, are now taking place. Also a series of mutual events of the moon's are about to start. The first is on September 10 involves a very slight penumbral eclipse of Ganymede by Callisto. At this event the change in brightness is too slight to detect. Some events later this year and in 2015 will be easier to see.
VENUS is also a morning object but not readily visible. It rises only half an hour before the Sun at the beginning of September and only 7 minutes earlier than the Sun by the 30th. The planet is in Leo much of the month but moves into Virgo on the 24th. On the 6th it will be less than 1° from Regulus, but with an altitude only 4° at sunrise, the conjunction will not be visible.
URANUS rises just before 9 pm on September 1st and close to sunset on the 30th. The planet is in Pisces with a magnitude 5.7.
NEPTUNE rises more than an hour before sunset the 1st and is highest just after midnight. The times get earlier by about 2 hours during the month, but start of NZDT drops it to only one hours earlier on the 30th. The planet is in Aquarius, magnitude 7.8.
PLUTO is in Sagittarius at magnitude 14.3, about 6° from Nunki, sigma Sgr. Nunki, at magnitude 2.1, is the brightest star in the handle of the teapot.
(1) Ceres and (4) Vesta are in Libra during September in the vicinity of Saturn. As noted above Vesta is in conjunction with Saturn on the 14th, Ceres' conjunction is early October. Their magnitudes change little in September at 9 and 7.8 respectively.
(6) Hebe brightens from magnitude 9.1 to 8.6 in the month. The asteroid starts September in Taurus but it moves into Eridanus on the 7th.
The follwing table lists various solar system object events during September. A list of astronomical terms used in may be found after the table.
|September 1||Mars 4.1 degrees south of the Moon|
|September 2||Moon first quarter|
|September 3||Moon southern most declination (-18.6 degrees)|
|September 4||Pluto 2.6 degrees south of the Moon|
|September 5||Venus 0.7 degrees north of Regulus|
|September 8||Moon at perigee
Neptune 4.3 degrees south of the Moon
|September 9||Moon full|
|September 11||Uranus 1.2 degrees south of the Moon Occn|
|September 15||Aldebaran 1.4 degrees south of the Moon|
|September 16||Moon last quarter
Moon northern most declination (18.6 degrees)
|September 20||Jupiter 5.2 degrees north of the Moon
Moon at apogee
Mercury 0.5 degrees south of Spica
|September 21||Regulus 4.4 degrees north of the Moon
Mercury greatest elong E(26)
|September 22||Pluto stationary|
Venus 3.8 degrees north of the Moon
|September 24||Moon new|
|September 26||Spica 2.4 degrees south of the Moon
Mercury 4.0 degrees south of the Moon
|September 28||Saturn 0.7 degrees south of the Moon Occn
Mars 3.1 degrees north of Antares
|September 29||Mars 5.6 degrees south of the Moon|
|September 30||Moon southern most declination (-18.5 degrees)|
- apogee: Furtherest point in the orbit of a body orbiting the Earth
- declination: 'Latitude' for celestial objects. The distance in degress above (north) or below (south) the celestial equator.
- perigee: Nearest point in the orbit of a body orbiting the Earth