* Astronomy

Blobrana · L

RE: September 2012

Blobrana · L

Observing Highlights for September: The Harvest Moon and Opposition of Uranus

The planet Uranus reaches opposition, or opposite the sun in the sky when it rises at sunset and sets at sunrise, on the same night as the Full Moon, September 29. Normally opposition is considered the best time to observe a planet, but when it occurs simultaneously with a Full Moon in the same region of sky, this is not the case. The moon will be just four degrees above Uranus, washing out the sky around the dim planet.
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Blobrana · L

Meteor Showers

There are no major meteor showers this month...
September is a month with the best sporadic rates and a few mysterious minor showers.
The Alpha Aquarids are active from Aug. 25 to Sept. 5, normally with a ZHR of 10. this year it may be quite active
The Delta Aquarids are active September 5 thru October 10, with a ZHR of 6. It is on view until dawn. Faint, swift meteors are likely and the brighter ones may leave persistent trains.
These two form part of what is known as the Auriga-Cassiopiea-Perseus-Aries-Triangulum radiants, active from late August until mid-October.
The Piscids, active September 1 - 30, have a ZHR of 3.
The Sextanids are active September 9 through October 9. Though, this one is more of a radio/radar shower. A new meteor shower, called the September Taurids, might peak this month on the evening of September 13 - 14. The exact date and time of maximum activity, however, are uncertain. The radiant, which lies between the Pleiades and Hyades star clusters, produces only 7 meteors per hour, with an average brightness of magnitude 2.7.

Shower	Activity Period	Maximum	Radiant		Velocity	ZHR
		Date	R.A.	Dec.	km/s
Alpha Aquarids	Aug 25 - Sept. 5	1 September	5.5h	41°	66.0km/s	10
October Arietids	Sept-Oct	8 September
Piscids	Sept 1 - 30	19 September	0.7h	9.2°	30.0km/s	5
Sextanids	Sept-Oct	25 September
Andromedids		26 September		58.1°	59.3km/s
Gamma Piscids	23 - 28	28 September	23.4h	11.0°	19.2km/s	4
Pi Virginids		29 September	12.6h	-16.0°	8.6km/s	3

Blobrana · L

Mercury: at magnitude -1.4, starts the month in the constellation of Leo. Mercury is best seen from 4.2h - 4.9h. The planet is 1.2° from Regulus on the 1st. Mercury is at superior conjunction on the 10th. Mercury is 5.5° from the Moon on the 16th.
(On September 1st, RA=10h10m38s Dec=+13°03.4' (J2000) Distance=1.276AU Phase k=93% Diameter=5.3")

Venus: is at magnitude -4.3. The planet is in constellation Gemini at the start of the month. It is best seen from 0.9h -17.3h. The Moon is 3.6° from Venus on the 12th.
(On September 1st, RA= 7h41m32s Dec=+19°21.0' (J2000) Distance=0.837AU Phase k=58% Diameter=19.9")

Earth: Autumnal Equinox is at 14:49UT, 22nd September

The Moon: Full Moon (diameter: 30.212') at 3:18.6 UT, 30th September. Lunar perigee (distance to moon center: 359398.3 km, apparent diameter: 33'15.0") at 2:41.0 UT, 19th September. Last Quarter Moon at 13:15.0 UT, 8th September. Lunar apogee (distance to moon center: 397880.1 km, apparent diameter: 30'02.1") at 5:58.3 UT, 7th September. New Moon (diameter: 32.185') at 2:10.6 UT, 16th September. First Quarter Moon (apparent diameter: 32.212') at 19:40.8 UT, 22nd September.

Mars: at magnitude 1.2 starts the month in the constellation Virgo. The Moon is 0.2° from Mars on the 19th.
(On September 1st, RA=14h13m05s Dec=-13°56.5' (J2000) Distance=1.807AU Phase k=91% Diameter=5.2")

Jupiter: is in the constellation Taurus. At magnitude -2.4, the planet is obserable in the morning sky. Jupiter is 0.6° from the Moon on the 8th.

Transit times of the Great Red Spot are posted in a seprate thread.
(On September 1st, RA= 4h53m07s Dec=+21°44.8' (J2000) Distance=5.011AU Diameter=39.3")

Saturn: at magnitude 0.8 sits in the constellation Virgo. The planet is best seen from 19.4h -20.2h. Saturn is 4.8° from the Moon on the 18th September.
(On September 1st, RA=13h40m22s Dec= -7°56.3' (J2000) Distance=10.426AU Diameter=15.9")

Uranus: is in the constellation Cetus. Uranus at magnitude 5.7, has a bluish-green hue and appears 3.6 arcseconds wide. Uranus is 4.7° from the Moon on the 2nd and the 30th. Uranus makes its closest approach to the Earth (19.061 AU, diameter 3.67") on the 28th September. The planet is at opposition on the 29th.
(On September 1st, RA= 0h28m25s Dec= +2°15.2' (J2000) Distance=19.166AU Diameter=3.7")

Neptune: is at magnitude 7.8 in the constellation Aquarius. The planet is best seen from 22.5h - 0.7h. Neptune is 5.7° from the Moon on the 27th.
(On September 1st, RA=22h14m19s Dec=-11°35.0' (J2000) Distance=28.996AU Diameter=2.3")

Pluto: is in the constellation Sagittarius (mag 14.1). Normally, a finder chart is necessary to help in identifying the 0.13" diameter dwarf planet. The dwarf planet is best seen from 21.1h - 3.2h. Pluto is very near to the Moon on the 23rd. Pluto is stationary on the 17th.
(On September 1st, RA=18h28m59s Dec=-19°35.0' (J2000) Distance=31.818AU Diameter=0.1")

The Sun enters the zodiac sign Libra at 14:49 UT, 22nd September.

Blobrana · L

Highlights

Autumnal Equinox
On this day, the Sun rises directly in the East, and sets directly in the West. At the South Pole, the Sun will begin to rise after six months of darkness.

Watch out for the zodiacal lights, also known as the false dawn, which maybe visible about two hours before sunrise from dark sites during the latter part of September.

                                 September
 d  h                                  d  h
 1  2  Mercury 1.2N of Regulus        18  4  Spica 0.8N of Moon      Occn
 2 20  Uranus 4.7S of Moon            18 11  Saturn 4.8N of Moon
 7  5  Moon at apogee                 19  3  Moon at perigee
 8  0  Aldebaran 4.5S of Moon         19 20  Mars 0.2N of Moon       Occn
 8 11  Jupiter 0.6N of Moon    Occn   21  9  Antares 5.6S of Moon
 8 13  LAST QUARTER                   21 23  Moon furthest South (-21.2)
 8 17  Moon furthest North (21.3)     22 14  Equinox
10 13  Mercury superior conjunction   22 19  FIRST QUARTER
12 15  Venus 3.6N of Moon             23  7  Pluto 0.4N of Moon      Occn
14  9  Regulus 5.5N of Moon           27  7  Neptune 5.7S of Moon
16  2  NEW MOON                       29  7  Uranus at opposition
16 11  Mercury 5.5N of Moon           30  1  Uranus 4.7S of Moon
17 20  Pluto stationary               30  3  FULL MOON