Go on, reach for the stars

By Catherine Smith

Allow time for your eyes to become accustomed to the dark and the rewards can be magnificent. Photo / Supplied
Allow time for your eyes to become accustomed to the dark and the rewards can be magnificent. Photo / Supplied

A still summer night seems like the perfect time to just lie on your back gazing at the stars, contemplating life and the universe, away from the TV and the bright city lights.

We asked David Britten, lifetime watcher of the skies and now astronomy educator at Auckland's Stardome Observatory, how you can figure out what's going on in the sky.

There is something very contemplative about the first steps David suggests: lie down on a patch of lawn or sand dune and gaze up. Better still, lie with your family or a group of friends, heads together in the middle and each gaze at "your" section of the sky. Allow five or 10 minutes for your eyes to adjust to the dark. This can take longer for older eyes: children can often see more things, more quickly, than adults.

An exciting activity is spotting meteors shooting across the sky. In a dark area with no light pollution (a remote area away from city lights or on a boat in the Hauraki Gulf) you may be able to see six or seven meteors an hour. Satellites can also be seen an hour or so after sunset and before sunrise.

A link on the Stardome website gives the times the International Space Station and other satellites are visible.

When learning the stars, "start with the Southern Cross: it is always in the night sky, and is bright and recognisable. At this time of year it is upside-down, low near the horizon almost due south, with two bright stars, Alpha and Beta Centauri (known as the Pointers), just to the west," explains David.

As you get out of the central city, you can also see the Milky Way galaxy. "It's a spectacular sight, with thousands of stars. For many people it's the first time they've seen it. It can be overwhelming, there are so many stars to see that you just can't see well from the suburbs," he says.

To keep your night vision, David suggests taping red cellophane over your torch, and looking at the bright moon last after you've finished looking at all the faint celestial objects. To see more, use binoculars with a magnification of about seven and a wide lens (look for "7 x 50"). Put them on a tripod to eliminate wobbles. "At this magnification, you can see craters on the moon as Galileo saw them 400 years ago," says David. With stronger binoculars (16x magnification) you can see the four brightest moons of Jupiter.

Slow down, become still and you'll start to see the gradual movement of stars and planets. The earth moves at 15 degrees an hour (approximately a hand width at arms length): if you are looking at a small patch of sky with a telescope this can be quite fast. "During the night it will rotate around a point in the sky called the South Celestial Pole (SCP). We are at latitude 37 degrees south, so the stars we see are rotating in our sky around the SCP at 37 degrees above the southern horizon, which is very helpful for direction-finding," David explains.

Just after sunset, the planet Jupiter is a bright light visible in the northwest, dipping lower in the west during January. The latest sunset is on January 7 and a full moon is on the 20th, when the fainter stars will be lost in the bright lunar glare. Saturn and Venus can be seen in the northwest before sunrise.

Stardome sells a comprehensive astronomical yearbook, or you can download charts of the night sky for each month. They can look daunting, but, again, start with the chart that has the Southern Cross to get your bearings. In January this is in the lower southern sky, towards the southeast. Then look around to the east to see the big star Sirius (the Dog Star), then Orion upside-down with his three belt stars between Rigel above and Betelgeuse below. Further north are the Pleiades, the cluster of stars that signal the start of the Matariki mid-winter festival marking the Maori New Year.

Galileo would have been excited by the the best development in astronomy today - almost instant communication. The internet has a wealth of images and information about space, space exploration and the universe, with video of the astronauts at the International Space Station, close-ups of the Martian landscape or the surface of alien moons and deep space images from orbiting space telescopes.

"Take the chance while you are on holiday to stay up late and see it all, or get up two hours before sunrise when the sky is at its clearest," says David. Brilliant.

More information

* stardome.org.nz for guides, programmes of events and more.

* skymaps.com for free downloadable charts

* Nasa.gov for links to missions, photographs and videos..

* apod.Nasa.gov/apod/ for latest space "picture of the day".

* spaceflightnow.com/ for up-to-date news on space missions.

* astronomy.org.nz to join the Auckland Astronomical Society.

- NZ Herald

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