Skynotes April 2014

Month Highlights

The outer planets, Mars, Jupiter and Saturn, can all be seen in the evening sky. Jupiter shines brightly in the north-west, while Mars and Saturn are found over in the east. By morning, the two inner planets, Venus and Mercury can be found in the east, rising just before the Sun.

Two Eclipses for April

Not one, but two eclipses will occur this month and both are partially visible from Melbourne.

Total Lunar Eclipse – 15th April

Just as the Sun sets on 15th April, there will be a red moon rising. This month's lunar eclipse begins while the Moon is still below the horizon. Just four minutes after maximum totality, the Moon will start to rise. It will likely appear quite red, both because it is low to the horizon and because the Sun's light must first pass through the Earth's atmosphere before reaching the Moon. Lunar eclipses are lovely to watch and best of all, you don’t need any special equipment just a clear eastern sky.

Maximum Totality 5:45pm
Moon Rises 5:49pm
Sunset 5:54pm
Totality Ends 6:24pm
Eclipse Ends 7:33pm

Partial Solar Eclipse – 29th April

Two weeks later, as the Moon changes phase from a Full Moon to a New Moon, we'll see a partial solar eclipse. The Moon and the Sun will come together in the afternoon sky and at greatest eclipse the Moon will cover 64% of the Sun's diameter. Shortly after, the Sun will set while still eclipsed by the Moon, so a good view of the north-western horizon will be needed.

Care must be taken when viewing a Solar Eclipse. Do not look at the Sun directly. The easiest way is to purchase special eclipse glasses from the Scienceworks shop. Alternatively, you can set up your own simple pin-hole camera to project an image of the Sun onto a flat surface. Check for details on the Planetarium website later in the month.

Eclipse Begins 3:58pm
Greatest Eclipse 5:07pm
Sunset 5:36pm

School Holidays

Scienceworks is open daily from 10am to 4:30pm during the School Holidays
(5 - 21 April; closed Good Friday). Planetarium session times are:

12pm: Tilt - come on a whirlwind adventure to find out how the seasons work.

1pm: Tycho to the Moon - meet Tycho, a dog who doesn't just howl at the Moon but wants to go there!

2pm: Ticket to the Universe - are you ready to take a trip to the far reaches of space? 

3pm: Our Living Climate - explore the science of Earth's amazing climate. 

See the Melbourne Planetarium's What's On listing for more details.

Sunrise & Sunset Times 

  Rise Set
Tuesday 1st 7:34* 7:14*
Friday 11th 6:43 6:00
Monday 21st 6:52 5:46
Wednesday 30th 7:00 5:35
*Daylight savings ends at 3am, Sunday 6 April

Moon Phases 

First Quarter Monday 7th
Full Moon Tuesday 15th
Last Quarter Tuesday 22nd
New Moon Tuesday 29th

The Moon will be at perigee (closest to Earth) on Wednesday 23rd at a distance of 369,764 km.

The Moon will be at apogee (furthest from Earth) on Tuesday 8th at a distance of 404,501 km.

Let the Moon Be Your Guide

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

  • Just after sunset on the 4th, the waxing crescent Moon is near Aldebaran (Taurus).
  • On the 7th, the First Quarter Moon is above bright Jupiter.
  • The waxing gibbous Moon sits near Regulus (Leo) on the 11th.
  • The Moon is above red Mars on the night of the 14th.
  • Mars and Spica (Virgo) sit just above the eclipsed Moon, at sunset on the 15th.
  • On the 17th, the waning gibbous Moon follows Saturn across the sky.
  • Before sunrise on the 26th, the waning crescent Moon is below bright Venus.

Planets

Mercury can only be seen for the first half of the month and then disappears below the eastern horizon as it moves too close to the Sun. The bright planet Venus sits above and to the left of Mercury and can be used to help find the fainter planet.

Venus is certainly putting on a show as the morning star. It is lovely and high in the east before sunrise and is joined by the crescent Moon on the morning of the 26th.

Mars can be found rising due east at sunset, with the bright star Spica sitting to the right. The planet is looking lovely and red in the evening sky, as it reaches opposition on the 8th. This means that Mars is in the opposite part of the sky to the Sun and also is at its closest to us. On the 15th, the eclipsed Moon will rise just below Mars and Spica.

Jupiter cannot be missed in the north-west at sunset. The twin stars of Gemini, Castor and Pollux lie to the right and Orion and Taurus can be found to the left. The First Quarter Moon sits above Jupiter on the 7th.

Saturn continues to follow Mars into the evening sky. The ringed planet rises about an hour after Mars and remains at the head of Scorpius. This magnificent constellation stretches out behind Saturn. The Moon travels across the sky with Saturn on the night of the 17th.

Meteors

The Lyrids is the main meteor shower in April. It is centred near the bright star Vega, which appears low to the northern horizon around 3am. The Lyrids is active between the 16th and the 25th, with a peak around the 22nd. Its hourly rate typically reaches 10, but occasionally outbursts occur when the meteor rate climbs to 100.

The Pi-Puppids is better placed for us but it is not a persistent shower. It is associated with Comet Grigg-Skjellerup and, being a relatively new shower, has periods of inactivity when the comet is far from the Sun. It peaks around the 23rd and the centre of the shower lies low in the south-west to the right of the bright star Canopus in Carina, the keel.

The delta Pavonids, which began in March, peaks on the 6th. This shower is centred on the little known constellation of Pavo, the peacock, which lies near the South Celestial Pole.

There should also be some meteor activity centred on Scorpius and Sagittarius that is best seen after midnight. Meteor activity in this region of the sky runs from the 15th through until July, with several peaks within this time.

Stars & Constellations

The Southern Cross can be found high in the south-east with the Two Pointers trailing behind. To the right of the Cross, in the south-western sky, is the star Canopus, the second brightest star in the night sky. Low in the south is Achernar, the head of the river Eridanus. Achernar never sets in Melbourne and is called a circumpolar star, along with the Southern Cross and the Two Pointers (Alpha and Beta Centauri).

April is the month for catching both the summer constellation of Orion, the hunter and the winter constellation of Scorpius in the sky together for a brief time after sunset. Orion can be seen lying on his side low in the west below Sirius, the brightest star in the night sky. Scorpius can be found rising in the east with the red star Antares marking the Scorpion’s heart.

International Space Station

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 – 5:00am, Wednesday 9th April.

The Station will appear in the north and travel right past Mercury before disappearing in the east.

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

On this Day

1st 1948, Alpha, Bethe and Gamow publish their famous paper analysing the 'hot Big Bang'.

2nd 1845, Fizeau and Foucault take the first photograph of the Sun.

3rd 1966, Luna 10 (USSR) became the first spacecraft to orbit the Moon.

4th 1979, Voyager 1 (USA) discovered the rings of Jupiter.

7th 1795, France adopts the metric system.

11th 1970, Apollo 13 (USA) was launched on its ill-fated mission.

12th 1961, Yuri Gagarin (Vostok 1 USSR) became the first human in space.

12th 1981, Columbia (USA) was the first space shuttle to be launched.

14th 1611, The word "telescope" is first used, by Prince Frederico Cesi.

18th 1971, Salyut 1 (USSR), the first space station, was launched.

21st 1990, The Hubble Space Telescope (HST) was launched on the space shuttle Discovery.

23rd 1971, First manned docking with a space station (USSR) was performed.

26th 1920, Harlow Shapley and Heber Curtis debated "The Scale of the Universe".

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