Skynotes December 2013

Best to rise early, if you’d like to see the planets this month. Jupiter, Mars and Saturn can be found stretched out across the sky, from north-west to north-east. A number of bright stars join them as well – Castor and Pollux  (Gemini), Regulus (Taurus) and Spica (Virgo).

Venus remains the evening star, although it is slowly moving towards the western horizon.

Comet ISON

On the morning of 29th November, Comet ISON passed within 1.6 million km of the Sun. Most of the comet seems to have been destroyed. However, the remaining debris is beginning to brighten. See the Museum Victoria Blog for further details: museumvictoria.com.au

Sunrise & Sunset Times

  Rise Set
Sunday 1st 5:52 8:26
Wednesday 11th 5:51 8:35
Saturday 21st 5:54 8:42
Tuesday 31st 6:00 8:45

Moon Phases

New Moon Tuesday 3rd
First Quarter Tuesday 10th
Full Moon Tuesday 17th
Last Quarter Wednesday 25th

The Moon will be at perigee (closest to Earth) on Wednesday 4th at a distance of 360,063 km.
The Moon will be at apogee (furthest from Earth) on Friday 20th at a distance of 406,267 km.

Let The Moon Be Your Guide

The Moon can be used as a pointer to find other objects in the sky.

  • On the morning of the 1st, the waning crescent Moon is low to the horizon between Saturn and Spica (Virgo).
  • The waxing crescent Moon sits to the right of Venus after sunset on the 6th.
  • On the night of the 16th, the waxing gibbous Moon is below Aldebaran (Taurus).
  • The waning gibbous Moon is above Jupiter on the morning of the 20th.
  • On the 26th the Moon sits above Mars.
  • The Moon is to the left of Spica (Virgo) on the 27th.
  • On the morning of the 29th, the Moon is near Saturn.

Planets

Mercury is too close to the Sun to be seen.

Venus begins sinking towards the western horizon. It has been stunning over the last few months as the ‘evening star’. On the 4th, the thin crescent Moon sits to the right of Venus.

Earth experiences the Summer Solstice at 4:11am on Sunday 22nd. This is when the Sun reaches its most southerly position for the year. On this day the Sun is at its highest and it is our longest day totalling 14 hours, 47 minutes.

Mars is high in the north-west before sunrise, sitting to the left of Spica (Virgo). On the 26th the Moon sits just above Mars.

Jupiter remains high in the north at sunrise with the twin stars of Gemini, Castor and Pollux. By the end of the month, the planet can be found rising in the east after sunset. The Moon travels with Jupiter across the sky on the 19th.

Saturn can be found rising in the eastern sky before sunrise. Sitting above Saturn is the bright star Spica (Virgo) and on the morning of the 4th, the crescent Moon sits between them. The Moon is also just above Saturn on the 29th.

Meteors

The most consistent meteor shower of the year, the Geminids, occurs between the 6th to 19th. It is quite active throughout this period, with a peak on the morning of the 15th. However, the waxing gibbous Moon around this time, makes it best to catch the shower a few days prior. The shower is centred near the bright star Castor, which rises in the north-east around 11pm and is visible until dawn. We can usually expect around 20 meteors per hour. This meteor shower is unique because it is associated with an asteroid called Phaethon, unlike other meteor showers that are caused by comet debris.

Stars & Constellations

The Southern Cross is now upside-down in the southern sky and the Two Pointers (Alpha and Beta Centauri) sweep just above the southern horizon. Sitting high in the south are the Large and Small Magellanic Clouds, two satellite galaxies of our own Milky Way Galaxy. These two galaxies can be seen as fuzzy patches from dark country sites. They lie close to 200,000 light years away and are slowly being drawn in towards our Galaxy.

Low in the north-west, the great square of Pegasus (the winged horse) can be seen. In dark skies and with a clear view to the northern horizon, you might just be able to see a faint fuzzy patch below Pegasus. This is the Andromeda Galaxy (M31), the most distant object visible to the unaided eye at 2 million light years away.

Orion, the hunter is back in our skies and can be seen in the north-east from sunset. For us in the south Orion appears to be standing on his head. Many people are familiar with the central stars of Orion that are commonly known as the Saucepan.

North of Orion is Taurus the bull, with the bright star Aldebaran marking the Bull’s fierce red eye. Also part of the constellation of Taurus is the cluster of stars called Pleiades or the Seven Sisters.

The two brightest stars in the night sky, Sirius (Canis Major) and Canopus (Carina), are found towards the south-east. Further south shines Achernar within the constellation of Eridanus, the river.

International Space Station

The ISS orbits the Earth every 90 minutes at an average distance of 400 km. From Earth, the ISS appears as a bright star that steadily moves across the sky. It can often be seen from Melbourne, for example at:

4:57am – 4:52am, Wednesday 18th December.

The Station will appear in the north-west, near the Moon and travel past Sirius (Canis Major) and the Southern Cross, before disappearing in the south-east.

Predictions of when to see the ISS can be obtained from the Heavens Above website.

On This Day

2nd 1971, Mars 3 (USSR) made the first softlanding and returned the first signals from Mars.

3rd 1973, Pioneer 10 (USA) made the first flyby of Jupiter and returned the first close-up images of the planet.

4th 1978, Pioneer Venus 1 (USA) became the first spacecraft to orbit Venus.

10th 1993, the faulty optics of the Hubble Space Telescope are repaired.

13th 1920, the size of a distant star, Betelgeuse in Orion, is measured for the first time at Mt Wilson Observatory (USA).

14th 1972, the crew of Apollo 17 (USA) were the last astronauts to walk on the Moon.

15th 1970, Venera 7 (USSR) made the first softlanding and returned the first signals from Venus.

24th 1968, Apollo 8 (USA) became the first manned craft to orbit the Moon.

25th 1758, the return of Halley's Comet, predicted by Edmund Halley in 1705, is observed by Johann Palitzsch (Germany).

31st 1744, James Bradley (UK) announces his discovery of the nutation (wobbling) of the Earth.

Subscribe to Skynotes

If you'd like Skynotes emailed to you each month, email us with your address. Or you can subscribe to the RSS feed.