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Posted on Nov 20, 2012

December 2012 Sky News

December 2012 Sky News

Mercury begins December in the constellation of Libra, before beginning a quick journey through Scorpius, Ophiuchus to finish December in Sagittarius before moving to Capricornus in mid January. It will be quite difficult to spot without a good low Eastern horizon. It will be difficult to observe as it will be too close to the Sun.

December 5: Mercury reaches inferior conjunction with the Sun.

December 12: Crescent Moon is only 1º south of Mercury

December 14: Mercury will be 25 arcminutes north of the star Graffias (Beta 1 Scorpii)

January 4: Mercury at Aphelion. Mercury reaches the farthest point from the Sun

January 18: Mercury reaches superior conjunction with the Sun – which means that the Earth and Mercury are on opposite sides of the Sun

January 24: Mercury at greatest latitude South.

Venus continues shines brightly as the ‘morning star’ starting December in Libra at magnitude -3.9 throughout December. Venus is much easier to spot than Mercury as it shines a magnitude -4 and is by far the brightest object in this part of the sky until joined by the Moon on the 12th of the month. It is close to Mercury and Saturn and forms a part of the so-called planetary alignment on December 21st with Saturn. It rises almost 90 minutes before the Sun for the entire month of December moving from Libra into Scorpius on the 19th and into Ophiuchus on the 23rd of the month. It will continue in the morning sky through January 2013 until in mid-February it becomes too close to the Sun to observe.

December 3: Venus, Mercury, Saturn and Spica make a nice line extending from the horizon.

December 4: Venus will be 1.2º north of the star Zuben Elgenubi

December 11: Limb of Moon 36 arcminutes south of Venus

December 12: Venus is close to the waning crescent Moon.

January 8: Venus will be 1° North of the Globular Cluster NGC6401 in Ophiuchus.

January 10: Venus will be 0.1° South West of the Trifid Nebula (M20) and 1.4° North of the Lagoon Nebula (M8) in Sagittarius.

 

Earth: December 21 – December Solstice. The December solstice occurs at 11:12 UTC. The South Pole of the earth will be tilted toward the Sun, which will have reached its southernmost position in the sky and will be directly over the Tropic of Capricorn at 23.44 degrees south latitude. This is the first day of winter (winter solstice) in the northern hemisphere and the first day of summer (summer solstice) in the southern hemisphere.

Mars: Low in the western sky at the start of December Mars will be setting just 2 hours after the Sun and is fading slightly in brightness to about magnitude 1.2. Now almost on the far side of the solar system the planet presents a very small image in amateur telescopes. It begins the month in Sagittarius moving into Capricornus on the 26th. The two-day old slim crescent Moon will be just north of Mars on the 15th. Mars remains an evening object throughout December and January. By the end of January it will be very low on the western horizon soon after sunset.

December 3:  Mars will be2.3º north of the star Nunki (Sigma Sagittarii).

December 9:  Mars will be 2.7º south of the star Pi Sagittarii

December 15: Mars will be South of the 2-day old crescent Moon.

December 26: Mars moves into Capricornus.

January 24: Mars at Perihelion

Jupiter: Jupiter is moving in a retrograde motion through Taurus throughout December and January.  The planet is at opposition on the 3rd of the month and will be visible all night long crossing the meridian at midnight. The giant planet will be at its closest approach to Earth and its face will be fully illuminated by the Sun. This is the best time to view and photograph Jupiter and its moons. Jupiter has 63 known natural satellites and even a good pair of binoculars will reveal the four Galilean moons orbiting the planet. The waxing gibbous Moon will be just to the west of the planet on the 25th and just east of it on the 26th. Just to the south of Jupiter lies Aldebaran and 10° to the planet’s north-west lies the Pleiades star cluster. The occultation of Jupiter by the Moon on the 22nd will not be visible in Australia.

Throughout January, Jupiter remains in Taurus close to the Hyades cluster

December 1-5: Jupiter close to open cluster NGC1647, Hyades and the red giant Aldebaran.

December 3: Jupiter is in opposition

December 23: Jupiter will be 1.8º north of the star Epsilon Tauri

December 24: Jupiter will be 1.8º south of the star Upsilon Tauri

December 25: Jupiter will be just to the East of the waxing gibbous Moon.

December 26:  Jupiter will be just to the West of the waxing gibbous Moon.

January 4: All 4 Galilean Moons are on the western side of the planet with the double star HD27639 near the planets southern pole.

January 22: Jupiter will be 0.5° north of the waxing gibbous Moon.

January 31st: Jupiter reaches the stationary point in its orbit and begins to move from West to East again across the star field.

January 31st: All 4 Galilean Moons are on the one side of the planet.

Saturn: Saturn, still in Libra, starts the month close to Venus and Mercury, then very quickly separates from the pair as the month progresses. It rises just after 4:00 am at the beginning of the month but by month’s end clears the eastern horizon around 2:20 am. The waning crescent Moon will be just south of Saturn on the 11th of the month. Saturn’s ring system is at its greatest tilt to the Earth for the year this month. At the present 19 degrees it still has a bit to go to reach the maximum tilt as seen from the earth of 27 degrees over the next 5 years.

In January Saturn remains in Libra where it will reside until May. By the middle of the month it will rise in the East at around midnight.

December 5:  Saturn will be 1.8º north of the star Lambda Virginis

December 7: Waning crescent Moon will be just above the planet.

December 10: Moon will be 3.2º south of Saturn

January 7: Saturn will be 4° North of the Moon.

 

Uranus is a still a reasonable target as it continues to move slowly east to west (retrograde) through the constellation of Pisces. It is visible low in the western sky.

December 13:  Uranus at eastern stationary point

Neptune is low in the evening sky still in Aquarius in December and the first half of January. By early February the planet becomes too close to the Sun for observation and does not appear again until its conjunction in mid-March.

 

Dwarf Planet – Pluto is a challenge in the crowded star fields to spot at magnitude 14.1 and in January returns to the eastern morning star after a conjunction with the Sun on December 31st. From our perspective, Pluto will appear to pass around the far side of the Sun, moving to within a mere 03°19′ of it in the night sky and becoming totally lost in its glare. Pluto will also pass apogee at around the same time – the time when it will be most distant from the Earth – since it will lie almost exactly opposite to the Earth in the Solar System. It moved to a distance of 33.34 AU from the Earth, making it appear at its smallest and faintest in the night sky. If it could be observed, it would measure 0.1 arcsec in diameter.

Pluto’s reaching solar conjunction marks the end of its 2011–2012 apparition as it withdraws completely from the evening sky, and the beginning of its gradual appearance in the pre-dawn morning sky over coming months, marking the beginning of its 2012–2013 apparition.

December 14: The Moon will be 1º north of Pluto

December 30: Pluto in conjunction with the Sun at 23:35 hrs

 

Minor Planets

Vesta remains in Taurus throughout December and January. It reaches opposition on December 9th brightening to a magnitude of 6.4. This makes it a not too difficult a target to find in binoculars. You will need a finder chart as it is in a cluttered part of the sky but will be relatively easy to find. Look low above the Eastern horizon after the end of the evening twilight. It is not far below Jupiter. After opposition it will start to fade again and by January 7th will be at Magnitude 7.

 

Ceres is also to be found in Taurus throughout December and January. At the start of December it will be at about magnitude 7.3 but it will brighten up to around 6.7 by December 18 when it reaches opposition.  It will them fade back to around magnitude 7.7 by the end of January.

 

January 9, 2013 the potentially hazardous asteroid (PHA) 99942 Apophis will make a close fly-by of the Earth at 0.097AU. It will be quite an interesting challenge to attempt to observe. It will be in the constellation Pyxis and low on the western horizon. On January 9 at around 9pm AEDT it will pass close to the 10th magnitude spiral galaxy 2784. At magnitude 14.4 it will need at least a 12-14 inch telescope to see.

 

The Moon in December, January:  Times given are UTC + 11 for Daylight Saving in NSW, ACT and VIC

November 28/29th Penumbral Lunar Eclipse in the early hours You will have to have good vision to see the slight darkening that occurs when the edge of earths outer shadow sweeps across the Moon. Mid-eclipse is 12:33 AEST on the 29th.  Times are in AEDT.

1st Contact:  November 28th 23:14:58

Greatest Eclipse: November 29th 00:33

4th Contact: November 29th 03:51:02

 

At the time of greatest eclipse the moon will only move through the penumbra of the Earth’s shadow, no part of the moon being in total eclipse. Thus there will be little noticeable change to the moon.

At mid eclipse almost all the moon will be in the penumbra, with its northern edge close to the umbra. As a result the northern part of the moon may look noticeably dull close to the time of mid eclipse. The moon will be visible for the entire period of the eclipse as seen from all of Australia.

Moon Phases

December 7: Last Quarter 02:32 AEDT

December 13: New Moon 19:42 AEDT

December 13: Moon at perigee 10:15 AEDT (357,073 km)

December 20: First Quarter Moon 16:19 AEDT

December 25: Moon at apogee 08: 21 (406,099 km)

December 28: Full Moon 20:21 AEDT

January 5: Last Quarter 14:58 AEDT

January 10: Moon at perigee 10:15 AEDT (357,047 km)

January 12: New Moon 06:44 AEDT

January 19: First Quarter 10:35 AEDT

January 22: Moon at apogee 21: 53 AEDT (405,311 km)

January 27: Full Moon 15:38 AEDT

 

Occultation

There is an occultation of Graffias , Beta 1 Scorpius,(mv= 2.56) by the Moon on December 12 between Moon occults the star (Beta 1 Scorpii, mv= 2.56) between 14:41 and 15:40.

 

Meteor Showers in December and January:

December 13, 14 – Geminids Meteor Shower. Considered by many to be the best meteor shower in the heavens, the Geminids are known for producing up to 60 multi-coloured meteors per hour at their peak. The peak of the shower usually occurs around December 13 & 14, although some meteors should be visible from December 6 – 19. The radiant point for this shower will be in the constellation Gemini. This year the new moon will guarantee a dark sky for what should be an awesome show. Best viewing is usually to the east after midnight from a dark location. Unfortunately for us observers in the Southern Hemisphere, the Geminid radiant never climbs far above the horizon, and this considerably reduces the number of Geminid meteors you are likely to see. Nevertheless, on the night of maximum, it is possible to see 20 meteors per hour coming up from the northern horizon.        Interestingly the Geminids are a meteor shower caused by the object 3200 Phaethon, which is believed to be a Palladian asteroid. This would make the Geminids, together with the Quadrantids, the only major meteor showers not originating from a comet.

January 3,4 – Quadrantids Meteor Shower. The Quadrantids  is a northern hemisphere shower, however it is possible to see for southern hemisphere observers to see some long-pathed meteors around the peak date of January 3rd and 4th. The radiant of this shower is an area inside the constellation Boötes. The name comes from Quadrans Muralis, an obsolete constellation that is now part of Boötes. It lies between the end of the handle of the Big Dipper and the quadrilateral of stars marking the head of the constellation Draco.

 

January 21- Eta Carinids Meteor Shower.  This is the shower best suited for January meteor viewing in the Southern Hemisphere and is active from 14th to 27th. The meteors are typically faint, with hourly rates of only 2 or 3 at the shower’s peak around the 21st. The shower is centred near the faint star Eta Carina, which is one of the most massive stars in our Galaxy. Eta Carina is found near the Southern Cross and is high in the south from midnight to dawn, the ideal time for meteor observing.

This meteor shower stream was discovered by C. S. Nilsson, from the University of Adelaide, from radio-echo observations made at Adelaide Observatory in 1961. Michael Buhagiar made the first visual observations from Perth. From observations made during 1969-1980, he determined the duration as January 14-28, with a maximum of only 1 per hour coming on January 21.

Some Bright Comets visible in December

C/2011 R1 (McNaught) reached Perihelion (2.080 AU) on the 19th October, 2012 and will be visible throughout the Spring and Summer with a magnitude currently of around 11.6 magnitude. It should be in the magnitude range of 11-13 for the next few months. It spends December and the first few days of January in Lupus before moving to Scorpius and fading to about 12th magnitude in January

 

Comet 168P/Hegenrother split apart into fragments on October 26. For those interested in viewing Hergenrother, with a larger-sized telescope and a dark sky, the comet can be seen in between the constellations of Andromeda and Lacerta. The comet fragments are considerably fainter than the nucleus.

 

Comet C/2011 L4 (Panstarrs) is in Lupus in December moving to Scorpius in early January, in the early morning sky near to C/2011 R1 (McNaught) you can see them both in an 12 inch telescope. It reached its minimum solar elongation of 12 degrees on November 27th. It is currently forecast to be one of the brightest comets of 2013. It is the morning sky in January and should increase in brightness from 9th to 7th magnitude by the end of January.

 

Comet C/2011 F1 (Linear) is slowly brightening predicted to be at magnitude 9.4 in December and should be visible in the early morning skies by January. It will be in the constellation of Sagitarrius.

 

Comet C/2012 F6 Lemmon will start off in Centaurus in January at 13th magnitude but as it moves rapidly towards the South it will become circumpolar moving through Crux and Chameleon and should be at around magnitude 11.

Sky Safari Pro can be used to produce maps to find each of these and other comets quite easily and it is what I have been using to identify the comets and their locations. Other references used are Simbad, NOAO and NGC/IC Catalogues and Astronomy 2013 Australia by Wallace, Dawes and Northfield and NASA JPL ftp://ssd.jpl.nasa.gov/pub/eph/planets/README.txt . Moon times are from the Geoscience Australia website http://www.ga.gov.au.

By Donna Burton