By IAN GRIFFIN*
The school holidays provide a great chance for children of all ages to explore the night sky.
Despite the shorter nights and daylight saving, many fascinating objects to excite the imagination are still on view in our October sky.
During the first fortnight of the month, it is possible to
see all of the bright planets during the course of a single night.
At evening's start, Venus shines brilliantly above the western horizon. Throughout early October it will be accompanied in the sky by Mercury, which will be visible as a less bright "star" slightly below and to the left (south) of the brighter Venus.
By month's end, Mercury's fast motion around the sun carries it into the glare of sunset, so be sure to look for it early this month.
Mercury and Venus set some 90 minutes after the sun. When they have gone, you have to wait a few hours to see other bright planets. Saturn rises above the northeastern horizon around 11.30 pm, followed an hour or so later by giant Jupiter.
Jupiter outshines the more distant Saturn, and can look like a bright searchlight as it clears the horizon in the early morning hours. Later still, just before sunrise, the planet Mars peeps above the northeastern horizon.
On October 24 the crescent moon will be close to the red planet, and will provide a useful location tool.
Jupiter and Saturn dominate the northeastern sky in the early hours of the day, when telescope owners can enjoy amazing views of Jupiters moons, and Saturn's rings. However, this month we turn our eyes to something much more distant.
During the middle of the night in October, low in the northern sky you can view the most distant object that can be seen with the unaided human eye.
This object is a galaxy in the constellation Andromeda. To the ancients this group of stars represented a pretty maiden, who was chained and exposed to a sea monster after her mother boasted of her superior beauty.
Although never particularly high in the sky from our part of the world, Andromeda is easy to see, especially if you get away from city lights.
To find our extragalactic neighbour, choose a dark, moonless night, with a clear sky. Begin by locating the Great Square of the winged horse Pegasus; this distinctive group of stars hangs low in the north at midnight throughout October. Below and to the right of the lower stars in the square lies the star Mirach, which can be used as a guide to help locate our quarry.
Below Mirach lies another star, and a line from Mirach, through this star extended the same distance again, reaches the position of the great nebula in Andromeda, which to the unaided eye looks like a dim, fuzzy patch of light.
This faint patch of light is actually a galaxy like our own Milky Way. It contains just over 100 billion stars, yet is so far away that to the unaided eye these blur into the smudge of light.
The Andromeda galaxy is over 2 million light years distant. In everyday terms this equates to (approximately) nineteen million million million kilometres.
The light hitting your eyes when viewing this object left at about the time the first hominids walked the African plains.
* Ian Griffin is director of the Auckland Observatory and Planetarium.
By IAN GRIFFIN*
The school holidays provide a great chance for children of all ages to explore the night sky.
Despite the shorter nights and daylight saving, many fascinating objects to excite the imagination are still on view in our October sky.
During the first fortnight of the month, it is possible to
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