Skynotes July 2016

Month Highlights

Mars, Jupiter and Saturn continue to shine brightly in the early evening sky. But towards the end of the month we are in for a real treat. After the 25th, Mercury and Venus will join the other planets in the evening sky, making it possible to see all five naked-eye planets together in the sky after sunset.

Juno Mission to Jupiter

Just after 1:30pm, July 5th (AEST), NASA’s Juno spacecraft will fire its engines to enter orbit around Jupiter. This amazing spacecraft will peer below Jupiter’s swirling clouds to reveal how the biggest, and most likely the first, planet in our solar system came to be formed. Juno will discover if Jupiter has a rocky core, it will analyse the composition of Jupiter, and investigate Jupiter’s intense magnetic field and its bright aurorae.

Planetarium Events

Discover the Night Sky

The Melbourne Planetarium at Scienceworks presents its popular after-dark sessions in August. All evenings include a glass of wine with cheese, the opportunity to chat to the Planetarium’s astronomer, Dr Tanya Hill, and to be immersed in a planetarium experience. You will finish the evening stargazing through telescopes (weather permitting).

Each evening will showcase a different aspect of the night sky. For more information, pricing or bookings please see the What's On or call the Scienceworks Booking Office on 9392 4819.

Sunrise and Sunset Times

    Rise Set
Friday 1st 7:36 5:11
Monday 11th 7:34 5:17
Thursday 21st 7:29 5:24
Sunday 31st 7:21 5:32

Moon Phases

New Moon Monday 4th
First Quarter Tuesday 12th
Full Moon Wednesday 20th
Last Quarter Wednesday 27th

The Moon will be at apogee (furthest from Earth) on Wednesday 13th at a distance of 404,271 km.

The Moon will be at perigee (closest to Earth) on Friday 1st and Wednesday 27th at distances of 365,982 km and 369,658 km, respectively.

Let The Moon Be Your Guide

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

  • Just before sunrise on the 2nd, the waning crescent Moon sits to the left of Aldebaran, a red giant star in Taurus, the bull.
  • After sunset on the 8th, the waxing crescent Moon is above Regulus, the kingly star of Leo, the lion.
  • Then on the 9th, the thin crescent Moon is just to the left of Jupiter.
  • The First Quarter Moon is near Spica (Virgo, the maiden) on the 12th.
  • During early evening on the 15th, the waxing gibbous Moon is near Mars.
  • On the 16th, the Moon travels across the sky with Saturn.
  • Before sunrise on the 29th, the waning crescent Moon is back with Aldebaran.

Planets

Mercury and Venus return to the evening twilight sky during the second half of the month. They are right next to each other on the 17th but are very low to the north-west horizon. By the end of the month, Mercury will sit above Venus in the north-west and near the bright star Regulus (Leo, the lion). For about an hour after sunset, all five naked-eye planets will be visible in a line stretching across the sky.

Earth reaches aphelion on Tuesday 5th. This is when the Earth is at its furthest point from the Sun for the year, at 152 million km. It is a coincidence that this occurs during our winter; the change in distance between the Earth and Sun during one orbit is small enough that there is no significant effect on daily temperatures.

Mars still looks lovely and red in the evening sky but is not quite as bright as it was last month. The planet remains at the head of Scorpius and can be found high in the north-east at sunset. On the 14th, the Moon is near Mars.

Jupiter can be seen in the north-west sky after sunset and on the 9th, the thin crescent Moon sits just to the left of Jupiter. Later in the month, Jupiter can be used as a guide to find Mercury and Venus; the two inner planets will appear below Jupiter and sit much closer to the horizon.

Saturn is found in the north-east at sunset sitting below the red supergiant star Antares which marks the heart of Scorpius. The Moon is just below Saturn on the night of the 16th.

Meteors

While July doesn’t have any strong meteor showers, there are a number of minor showers that combine to produce good results during the later half of the month. The area of sky to watch is around the constellations of Aquarius and Capricornus and as always, the best time to spot meteors is after midnight. The main meteor shower for July, the Southern Delta Aquarids, peaks on the 28th.

Stars and Constellations

In the west in the early evening is the kite shape of Corvus, the crow, sitting just below the bright star Spica, in Virgo. The Southern Cross is high in the south while the bright stars Canopus and Achernar are found low to the southern horizon.

Almost overhead, Scorpius takes up a large part of the sky with the hook shape of its tail. Sitting below the tail of Scorpius is the teapot shape of Sagittarius.

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:

6:12pm – 6:17pm, Monday 4th July.

The Station will appear lovely and bright above the north-west horizon, passing Jupiter, before travelling towards the south-east and crossing right through the Two Pointers (Alpha and Beta Centauri).

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

On This Day

4th 1997, Mars Pathfinder (USA) lands on Mars.

4th 1054, Chinese and other astronomers witnessed the supernova explosion that produced the Crab Nebula.

6th 1687, Isaac Newton (UK) published 'Principia Mathematica'.

8th 2011, The space shuttle Discovery (USA) was launched on the final mission for the shuttle program.

10th 1962, Telstar (USA) the first private telecommunications satellite was launched.

11th 1979, Skylab 1 (USA) was destroyed during re-entry over central Australia.

14th 1965, Mariner 4 (USA) made the first controlled flyby of Mars and returned the first close-up images of the planet.

15th 1975, the first USA/USSR space project Apollo-Soyuz was launched.

17th 1850, W.C. Bond and J.A. Whipple (USA) take the first photograph of a star.

20th 1969, Apollo 11 (USA) lands on the Moon. At 12:39pm AEST (21st) Neil Armstrong became the first person to walk on the Moon.

23rd 1999, The Chandra X-ray Observatory (USA) is launched from the space shuttle Columbia.

25th 2000, The International Space Station starts to take shape with the installation of the Russian Service Module.

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