Mapping our sky: a winter guide to the stars

Updated July 16, 2014 16:44:20

For more than 20 years, Geoff Wyatt has helped guide and educate many Sydney residents and visitors about the objects in our sky.

Last year, this would have included the 180,000 people who came through the doors of Sydney Observatory.

Since his childhood, his own world view has been sculpted by his skyward perspective.

"My first telescope was actually my brother's. It was given to him when I was about 6 or 7," he said.

"He made me stay outside while he found Saturn. I was completely underwhelmed by the view but impressed by his determination to find it. I've loved science ever since.

"I even timed my honeymoon to see a comet from Hawaii in 1997 and just last year went to see the aurora from the Arctic Circle."

In his role as guide and Education Officer at the observatory, Geoff has spent countless hours re-versioning astronomical complexities into bite size pieces of information.

Offering a practical guide to all things star-gazing, Geoff explains the equipment, locations and knowledge that you'll need to prepare for the best experience.

The role of the seasons in stargazing

Temperatures aside, Geoff said the seasons are very important in the kind of view they offer us.

"In winter, it's better in terms of seeing - it's clearer, more often in winter than in summer," he said.

"Less humidity - steady, clear skies, so you can get a very sharp view and pinpoint stars."

As we orbit the sun, our view of the night sky in winter and summer also changes.

"In winter, we have the best part of the view, the Milky Way, and the centre of the Milky Way is passing overhead during the winter months.

"There are lots of good objects to look at in the summer sky but that very bright band of the Milky Way is best seen in the early hours of the winter evening sky."

According to Geoff, atmospheric conditions like light pollution and humidity also affect the view, ranging in severity between the summer to winter months.

"The main problem is light pollution, that doesn't really differ from summer to winter. In some regards it can ... more open fireplaces [in winter].

"It is mainly the humidity affecting the view from summer to winter and of course you tend to get more clouds in general over the summer months, more storms than in winter, so you do typically have clearer skies more often in winter."

The best sky-watching locations in Sydney

Ask Geoff what his top pick is and he's quick to nominate his own front lawn.

Outside his area however, his suggestion for the best sunrise is the Lighthouse Park at Vaucluse. For a spectacular sunset, he recommends the Dudley Page Reserve at Dover Heights.

If you're in search of the best stargazing locations, Geoff said you'll need to go anywhere west or south of the city.

"In winter, you've the Milky Way high over Sydney. If you go to the north, you're looking back over the glow of Sydney.

"If you're just up at the mountains or to the south of Sydney, you're looking back towards the darker parts of the south of the city, so you don't have the lights in the way."

The main things to gaze at

Geoff's first recommendation is searching for the Milky Way.

"If people can get away from the city and look up and see that bright band of the Milky Way, I think it tends to take most people's breath away, for the first time when they look at it," he said.

"Even some of us, after we've looked at it thousands of times, the view of that blazing across the sky is quite spectacular."

The region around Sagittarius and Scorpius is where you'll spot Milky Way is at its brightest.

Stretching from there down to the Southern Cross, Geoff said you'll find dark patches against the Milky Way, which represents the emu in the sky - important to Indigenous communities across Australia.

Towards the Southern Cross, specific objects like Alpha Centauri come highly recommended.

"Even through a good pair of binoculars, you'll be able to see it split and resolve into a binary star.

"It's two stars locked together in a gravitational dance. It's the nearest star to us after the sun, four light years. So, you're looking at it as it was four years and four months ago."

The Southern Cross constellation and an open cluster of stars next to the second brightest is called NGC-4755 (known as the 'Jewel Box').

Omega Centauri nearby, is what Geoff refers to as "an absolute cracker".

"It's a globular cluster - a big ball of stars - that's in the order of about 15,000 to 20,000 light years away. It's probably the core of another galaxy that the Milky Way has absorbed."

There are around 140 globular clusters associated with the Milky Way that we can see.

Another one better seen from the city of Sydney is 47 Tucanae (or NGC 104).

"Those two objects are two of the best you can look at from the Southern Hemisphere in winter and of course we get a better view than people in the north so that's even better."

Becoming a stargazing master from your own backyard

Citing location as the prime factor, Geoff offered the following words of wisdom to help create the right stargazing environment.

"You need to find somewhere that's got a clear view, no bright lights, no fireplaces, no moon," he said.

In terms of equipment, Geoff recommends a blanket, pillow, binoculars, hot chocolate and a navigational guide - many podcasts and apps can also help with this.

Investing in a telescope is not always necessary.

"I think you'll find lots of people that have big telescopes in the garage that they don't use.

"A small telescope with a clear view that's used often beats a big telescope in storage that's too heavy to get out and too difficult to set up."

As for taking your skills from amateur to expert, Geoff says practice is the key.

"If you familiarise yourself with the major constellations - the zodiac constellations - it's a good place to start, then you've got the [Southern Cross].

"It's just practice makes perfect, you become familiar with it and then star-hopping becomes second nature."

Topics: education, science, human-interest, science-and-technology, astronomy-space, galaxies, planets-and-asteroids, space-exploration, stars, telescopes, sydney-2000

First posted July 16, 2014 15:23:26