Summer Constellations

We live on a planet that is constantly moving, which affects what we see in the sky. As the Earth rotates on its axis, we experience day and night. As the Earth orbits around the Sun, we experience the seasons. For each season we see different constellations in the night sky. For example, the constellation of Scorpius is best seen during winter, while the constellation of Orion is visible on summer evenings. The Southern Cross is a good constellation to watch throughout the entire year because it never disappears below the horizon. It can always be seen circling around the South Celestial Pole.

The information given is for around 8pm (AEST) during December.

Southern Cross in Summer

The Southern Cross in Summer
Copyright: Melbourne Planetarium

In the night sky:

The Southern Cross and the Two Pointers are nearly upside down and very low in the south.

The Milky Way is low in the east arching from north to south.

The star Achernar is high in the south with Canopus trailing behind in the south-east.

Orion, the hunter, can be seen in the north-east. It contains the bright stars Betelgeuse and Rigel. Between these two bright stars is a line of three stars called Alnitak, Alnilam and Mintaka, that mark the belt of Orion. Orion's belt is more commonly recognised in Australia as the base of the Saucepan.

To the west of Orion, is the triangle-shaped face of Taurus the bull. This is a cluster of stars called the Hyades. The bright orange-red star, Aldebaran, marks one eye of the bull. In Taurus there is another faint cluster of stars called the Pleiades or Seven Sisters.

With 7 x 50 binoculars:

The magnificent Great Nebula in Orion is visible as a cloudy star in the sword of Orion (or handle of the Saucepan). The Pleiades and Hyades clusters in Taurus are also spectacular with binoculars.

With a telescope:

The Horsehead Nebula can be seen near the star Alnitak in the belt of Orion.

Below Aldebaran is a faint star which marks the tip of one horn of Taurus and close to this is the Crab Nebula, the remnant of an exploded star discovered in 1054 AD.

Low in the northwest, is the Andromeda galaxy. It is 2,200,000 light years away and stretches 180,000 light years across.

Comments (2)

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Aidan 13 February, 2013 08:13
Hi there,Why is the Southern Cross very nearly directly overhead at 4Am in summer, while the sun is as far south on the ecliptic as it will ever be.It seems to me that Crux should be as far south as it can be, my dilema.
Discovery Centre 15 February, 2013 17:02
Hi Aidan. At 4am in February in Melbourne the Southern Cross is high in the sky and almost directly south, however at 4am in August it is low down near the horizon.  Now the Sun moves in an arc - see the following link on the Sun’s movement from summer to winter. The Sun’s movement is due to the Earth’s axis being tilted 23 ½ degrees, and as we move around the Sun during the year the path of the Sun in the sky changes.  When we look at the stars, you need to remember that the axis of the Earth always points towards the celestial poles, and as we move around the Sun what we can see depends upon the angle at the time.
In short, when you look at the night - say at 4:00am in summer - the Southern Cross is high in the sky, but 6 months later in winter when the Earth moves directly opposite, the angle to the Southern Cross has changed due to the tilt of the Earth’s axis. So at the same time of day the constellations will all be that much lower on the horizon.
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