Skynotes October 2009

Month Highlights

October is a good month for early risers with the planets Mercury, Venus, Mars and Saturn all visible in the morning skies. Jupiter is alone in the evening sky but is shining brightly.

Lunar Impact

On the night of October 9 (Melbourne time) a small probe will crash into a crater near the Moon's south pole to try to determine whether it contains water. The impact will create a shower of debris around 10km high which an orbiting satellite, LCROSS, will fly through to look for the tell-tale signs of water ice. Although the crater itself, Cabeus A, is in permanent darkness, and so a likely place to find ice, the shower will be lit by sunshine and it may be possible to see the impact with a good backyard telescope (of at least 10" aperture). Details can be found on NASA's website.

Sunrise & Sunset Times

Moon Phases

The Moon will be at perigee (closest to Earth) on Tuesday 13th at a distance of 369 067 km.
The Moon will be at apogee (furthest from Earth) on Monday 26th at a distance of 404 166 km.

Let the Moon be Your Guide

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

• Throughout the evening of the 1st the Moon follows the planet Jupiter through the sky.
• For a few hours after midnight on the night of the 7th, the Moon lies alongside the star cluster Pleaides low on the northern horizon.
• Before sunrise on the 12th the Moon sits alongside Mars and above the twin stars of Gemini, Castor and Pollux.
• On the morning of the 15th the Moon is near Regulus (Leo).
• After the sunset of the 21st, the thin crescent Moon, just-visible, lies beneath the bright star Antares (Scorpius).
• During the night of the 27th the waxing gibbous Moon is back near Jupiter.

Planets

Mercury can just be seen in the morning sky early in the month. It reaches its maximum distance from the Sun on the morning of the 11th but unfortunately for us remains close to the horizon. On the morning of the 8th it lies just over one lunar diameter away from the planet Saturn with the planet Venus nearby as well. This grouping remains tight between the 7th and the 13th of this month.

Venus is the 'morning star' throughout the month, shining brightly in the eastern sky before dawn. It forms a nice grouping with Mercury and Saturn this month.

Mars is in the morning sky, higher up than Venus but much less bright. On the morning of the 12th the last quarter Moon sits beside Mars.

Jupiter is high to the north at sunset and remains in the sky until after midnight. Although continuing to fade after maximum brightness in August it is still very bright. The waning gibbous Moon lies below Jupiter on the night of the 1st and the waxing gibbous Moon again lies alongside it on the 27th.

Saturn is the morning sky, rising earlier throughout the month. On the 8th it passes very close to the planet Mercury while on the morning of the 14th it passes nearly as close to the bright planet Venus.

Meteors

The Orionids are visible from the 15th to 29th, with the peak of the shower occurring on the 21st. This is a good shower for beginners with estimates of around 30 meteors per hour. This should be a particularly good year with a strong peak forecast, and the last-quarter Moon allowing dark sky viewing. The best time for viewing will be from around 3am on the morning of the 21st until an hour before sunrise. The shower is centred on Orion’s club near the red supergiant star Betelgeuse and the meteors are typically fast, sometimes bright and generally more than half leave persistent trains. This shower was first recorded by the Chinese in 288 AD and is associated with Comet Halley.

The Taurids are a long-duration shower visible throughout spring and peaking during the first week of November. There are two branches to the shower: one appearing near the star cluster Pleiades and the other near the red star Aldebaran. Each branch has a maximum rate of roughly ten meteors per hour. They have been described as being bright, slow-moving and with the occasional colourful fireball.

Stars & Constellations

Scorpius, known by its bright red star Antares, and Sagittarius, the archer, can now be found low in the west.

Just above the north-west horizon we see the constellation of Lyra and its brightest star Vega. 

To the north and also close to the horizon, it is possible to make out the large cross shape of Cygnus with its brightest star Deneb. The three main stars in Aquila lie high above the northern horizon; the bright central star is Altair. Above the north-eastern horizon, four stars make out the square shape of Pegasus.

Over in the south-east, Achernar shines brightly at the head of the river Eridanus. A little further south but much lower in the sky is Canopus, the second brightest star in the night sky. The Southern Cross is now found in the southwest with the Two Pointers almost vertical above it.

International Space Station

The ISS orbits the Earth every 90 minutes at an average distance of 400 km. From Earth, it appears as a bright star that steadily moves across the sky. It can often be seen from Melbourne, for example at: 8:25pm – 8:31pm, Wednesday 7th October.
The Station will appear in the north-west and travel through the northern sky, passing bright Jupiter before disappearing towards the south-east.

Predictions of when to see the ISS can be obtained from the Heaven's Above website. 

On This Day

1st 1958, NASA (National Aeronautics and Space Administration) was inaugurated.

3rd 1815, the first meteorite identified as coming from Mars fell in Chassigny, France.

3rd 1942, German A-4 (V-2) rocket becomes the first rocket in outer space.

4th 1957, Sputnik (USSR) was launched to become the first artificial satellite.

5th 1923, Edwin Hubble establishes that M31, the Andromeda Galaxy, is separate to and distant from our own Milky Way Galaxy.

6th 1990, Ulysses (Europe) was launched to the poles of the Sun from the space shuttle Discovery.

7th 1959, Luna (USSR) took the first images of the far side of the Moon.

10th 1846, William Lassell (UK) discovered the first moon of Neptune,Triton.

10th 1980, the Very Large Array (VLA) telescope network is commissioned.

10th 1986, Cruithne, the satellite of the Earth with a horseshoe orbit is discovered.

11th 1968, Apollo 7 (USA), the first manned Apollo mission was launched.

14th 1947, Charles E. ‘Chuck’ Yeager made the first supersonic flight (Bell X-1).

15th 1582, the Gregorian Calendar is established.

15th 1997, the spacecraft Cassini was launched.

18th 1989, the spacecraft Galileo was launched to Jupiter from the space shuttle Discovery.

21st 1923, the official opening of the world's first projection planetarium, Deutchse Museum, Munich.

22nd 2136BC, the first recorded solar eclipse is observed in China.

23rd 1975, Venera 9 (USSR) returned the first images of the surface of Venus.

31st 1992, the Catholic Church admits it erred in condemning Galileo's beliefs.