Glancing up at the night sky in Chicago gives amateur astronomer John Spack little cause for awe.

Like most major cities, Chicago's bright lights block out everything but the moon and the most brilliant stars and planets.

So on clear nights, the 51-year-old accountant climbs up a narrow ladder off his bedroom and squeezes himself into a $25 000 observatory he built onto the side of his house.

"There's Saturn," he said as he adjusted the instruments on his telescope and a light wind blew in through the open dome. "You can see the rings."

Light pollution is so pervasive in the United States that two thirds of Americans can't see the Milky Way from their backyard and the glow from some cities can be seen as far as 322 kilometres away, according to the National Parks Service.

The biggest culprit is poorly-designed fixtures which aim light upwards or sideways. They are also colossal energy wasters. Switching to shielded fixtures which focus the light downward could cut national electricity use by between $2-billion and $5-billion a year, the parks service estimates.

"How can people get interested in something if they look up and see an orange glow?" said Peter Strasser, a technical advisor to the International Dark Sky Association.

"People literally don't know what they're missing."

Improving

But as development continues to spread across previously dark rural areas, some relief is coming from a growing interest in energy efficiency and night sky friendly lighting.

Hundreds of US municipalities have enacted ordinances which address light pollution and manufacturers have expanded their production of shielded and low-energy lighting, Strasser said.

While the skies are getting brighter and brighter, the advent of affordable high-powered telescopes has helped keep amateur astronomy alive, said Marni Berendsen of the Night Sky Network of astronomy clubs.

"The telescopes amateurs can get a hold of these days are in many ways professional instruments so they can do professional work," she told AFP.

Some researchers actually farm out some of their exploratory work to amateurs because telescope time at professional observatories is booked for months or years in advance, she said.

Easier to find stars

Remote telescopes that can be controlled over the internet also give amateurs "the capability of doing dark sky work from the comfort of your light-polluted back yard or living room," Berendsen added.

For Spack, the observatory was a way to buy himself more time with the stars. He was drawn to the heavens as a child but soon gave up the hobby because his manual telescope was too much work.

Computer-directed "go-to" telescopes made it a lot easier to find what he was looking for, but the equipment was cumbersome and too costly to leave unattended.

Now he scans the solar system on a whim.

"I'll wake up, see that it's clear, put on some warmer clothes and just open up the dome and away you go," he said.

"Within 10 or 15 minutes I'll be observing. Before I wouldn't have done that."

One night he sat for hours watching a moon emerge from behind Jupiter. During the last lunar eclipse, he captured a star slipping behind the moon over a 20 minute period on his digital camera. And then there was the time he glimpsed a star hidden in the centre of a nebula ring.

"It would be nice to discover a comet," he said. "You just have to be at the right place at the right time. You never know."

AFP