Skynotes February 2017

Month Highlights

It’s the last chance to see Venus and Mars in the evening sky. They can be found chasing the Sun in the western sky after sunset. Jupiter, Saturn and Mercury are all visible in the pre-dawn sky.

Regulus hides behind the Moon

During the early hours of the 12th, the Full Moon will pass directly in front of the bright star Regulus. The star will be hidden behind the Moon for almost 90 minutes.

As mentioned in last December’s Skynotes, every 9 years, the Moon’s path aligns almost perfectly with the ecliptic or the path the Sun appears to follow in the sky. The star Regulus, in the zodiac constellation of Leo of the lion, is the brightest star that sits very close to the ecliptic. Therefore, for a period of time, we will see the Moon pass directly in front of or occult the bright star Regulus, as the Moon passes by the star each month.

The occultation can only be seen from certain locations and this month, it works perfectly for Melbourne, and most of Australia. We will also see another occultation later in May.

The Moon will meet up with Regulus at 12:28am, when the star will disappear behind the right-side of the Moon. The star will emerge from the left-side of the Moon at 1:51am.

The Moon will be high in the north at this time. However, seeing the precise moment when Regulus disappears and later emerges will be difficult because of the brightness of the Full Moon. It’s best to observe a few minutes before Regulus disappears and it should be possible to see Regulus a few minutes after the expected reappearance time.

Planetarium Events

Valentine's Under the Stars - 13th / 14th February

Take your seat at the centre of the Universe to uncover the mysteries and mythologies written in the stars that have filled lovers with wonder and awe for thousands of years. This special evening includes a tour of Melbourne's night sky, along with Melbourne Planetarium's fulldome production Capturing the Cosmos. Bookings essential. For details call 13 11 02 or visit the Planetarium's What's On listing.

Sunrise & Sunset Times

  Rise Set
Wednesday 1st 6:34 8:33
Saturday 11th 6:45 8:23
Tuesday 21st 6:56 8:11
Tuesday 28th 7:03 8:01

Moon Phases

First Quarter Saturday 4th
Full Moon Saturday 11th
Last Quarter Sunday 19th
New Moon Monday 27th

The Moon will be at perigee (closest to Earth) on Tuesday 7th, at a distance of 368,816 km.

The Moon will be at apogee (furthest from Earth) on Sunday 19th, at a distance of 404,375 km.

Let the Moon be Your Guide

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

  • After sunset on the 1st, the waxing crescent Moon sits just above Venus and Mars.
  • On the 5th, the waxing gibbous Moons sits to the left of Aldebaran (Taurus, the bull) and above the lovely star cluster Pleiades.
  • The twin stars of Gemini, Castor and Pollux sit below the Moon on the 9th, while the bright star Procyon (Canis Minor, little dog) can be seen above.
  • At 12:28am, on the 12th the Full Moon will pass in front of the bright star Regulus (Leo, the lion) briefly hiding it from view. The star will reappear at 1:51am.
  • On the morning of the 16th, the waning gibbous Moon can be found just below Jupiter and the bright star Spica (Virgo, the maiden).
  • The Last Quarter Moon sits directly to the left of the red supergiant star Antares (Scorpius) on the morning of the 19th.
  • Before sunrise on the 21st, the waning crescent Moon can be found to the left of Saturn.

Planets

Mercury is low towards the eastern horizon before sunrise. It can be seen during the first half of the month but then moves too close to the Sun to be visible.

Venus and Mars are together in the evening sky after sunset as they make their way towards the western horizon. Venus as always is eye-catching, while Mars is much fainter and can be found just above and slightly to the right of Venus. On the 1st, the crescent Moon sits just above Mars.

Jupiter is high in the north at sunrise and remains paired with the bright star Spica (Virgo, the maiden) which sits just above the planet. On the morning of the 16th, the Moon can be seen just below Jupiter.

Saturn appears in the east before sunrise. It sits below the constellation of Scorpius and is near the brightest part of the Milky Way, marking the centre of our Galaxy. The Moon can be found to the left of Saturn on the morning of the 21st.

Meteors

The alpha-centaurids and beta-centaurids are active from the 2nd through until the 25th, with a peak on the 8th. The two showers have distinct characteristics, but in practice it is difficult to distinguish between them. These showers are perfect for us as they occur near the bright Two Pointers that lead the way to the Southern Cross. Although the showers are not generally strong, they often produce many bright meteors including some fireball types and some leave fine persistent trails. On good occasions rates of 25 meteors per hour have been recorded although lower rates of around 6 meteors per hour have been more usual in the last decade.

Stars & Constellations

Orion, the hunter, can be seen high in the northern sky this month. This constellation appears upside down in the Southern Hemisphere and is best recognised as the Saucepan, with Orion's belt making up the base of the saucepan and Orion's sword as the handle. Above the saucepan is the blue-white supergiant star Rigel, one of Orion’s legs, and below it is the red supergiant Betelgeuse, marking Orion’s shoulder.

The Southern Cross and the Two Pointers are low in the south-east which means that the Magellanic Clouds, our two nearest galaxies, are high in the sky. Away from city lights, the Magellanic Clouds can be seen as two fuzzy patches, hence their name.

International Space Station

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

5:35am – 5:45am, Saturday 4th February.

The Station will appear in the north-west and travel past Jupiter, Saturn and Mercury before disappearing in the south-east.

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

On This Day

1st 2003, the Space Shuttle Columbia (USA) was destroyed as it re-entered the Earth's atmosphere.

2nd 1931, the first mail delivery by rocket was made in Austria.

3rd 1966, Luna 9 (USSR) made the first softlanding on the Moon, and transmitted the first images from the Moon.

3rd 1966, the USA launched its first operational weather satellite, ESSA-1.

5th 1974, Mariner 10 (USA) returned the first close-up images of Mercury.

6th 1971, the first golf ball was hit on the Moon, Apollo 14 (USA).

7th 1984, Bruce McCandless, from Challenger (USA) made the first untethered space walk.

11th 1970, Japan became the fourth nation in space with the launch of Osumi-5.

14th 1963, Syncom 1 (USA), the first geosynchronous satellite, was launched.

15th 1564, Galileo Galilei was born.

18th 1930, Clyde Tombaugh (USA) discovered Pluto.

19th 1986, MIR (USSR), the first permanent space station, was launched.

20th 1962, Friendship 7 carried the first American astronaut into Earth orbit.

23rd 1987, SN1987A, the closest and brightest supernova since 1054 was discovered.

24th 1968, Jocelyn Bell (UK) discovered the first pulsar.

27th 1942, JS Hey (UK) discovered radio emissions coming from the Sun.

 

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