So many astronomers, so little time -- telescope time that is.

Todays behemoths cost hundreds of millions of dollars. Since individual ownership is impossible they must be shared. Until now.

Later this year, at a cost of slightly more than a million dollars, a team of astronomers has exclusive use of a telescope larger than the Mount Palomar giant. What makes it inexpensive is not the ski-chalet-like wood frame observatory or the aluminum tubes that suspends the instruments over the main mirror, but the mirror itself.

By a happy accident of physics, a spinning liquid forces its surface into the perfect shape for a telescope mirror. Capitalizing on this, scientists at the University of British Columbia (UBC) have built a 236-inch (6-meter) Liquid Mirror Telescope, or LMT, set to capture its "first light" later this summer.

A telescope mirror's job is to hold a thin reflecting layer in the right shape. Over the years astronomers have used polished metal, solid glass and large mirrors created from many smaller ones.

The LMT uses a dish of liquid mercury. If it works, "classical telescopes with solid mirrors will go the way of the great refractors that were replaced with reflecting telescopes," said physicist Ermanno Borra.

Imagine a lazy Susan holding a bowl full of water. When spinning, the water's surface becomes the perfect shape for a telescope mirror. If the liquid is mercury, an excellent telescope mirror is formed, the core of a Liquid Mirror Telescope [LMT].

Cosmologist Paul Hickson is using this physics to make the world's 13th largest telescope. It collects starlight with a plate of mercury 6 meters across spinning at about 5 rotations per minute.

This University of British Columbia telescope costs about $1 million. A conventional telescope with a regular solid glass mirror of the same size would require an outlay of about $100 million. A large part of the savings comes from not making, polishing, testing and mounting a standard mirror.

The low cost means Hickson and his fellow cosmologists are able to afford a large telescope for their exclusive use to do the science they would like to do -- but can't.

"I didn't start out to be a telescope builder. I only wanted to build a telescope, collect good data and get scientific results," Hickson said.

It sounds simple: Spin a plate of mercury, place a camera above it at the focal plane and -- voila -- a telescope is born. Yet making it work wasn't easy.

The concept of LMTs can be mapped back to the 18th century. Experiments that utilized the concept were conducted in the 1800s and the early 1900s, but the results were disappointing.

The concept was sound, but the technology available was too crude to make it work.

Vibrations from the ground around the telescope made image-smearing waves in the mercury. To achieve sharp images, the focal plane must not move. This requires the rotation of the vessel holding the mercury to vary less than one part in 100,000 during the exposure.

Following these experiments, LMTs were a curiosity in the history of physics until the early 1980s. "It was nearly a forgotten concept that had a bad reputation because past attempts were unsuccessful," said Borra.

After rethinking the idea, he thought that this mirror married to modern technology would give birth to a large, cheap telescope.

In Borra's Laval University lab he began to first experiment with a 19.7-inch (50-centimeter) mirror, quickly progressing to one at 39.5 inches (1-meter). After about a decade, he fabricated a mirror that produced images equal to those made by conventional glass mirrors.

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He and his students figured out how to use air bearings to support the vessel holding the mirror. To get sharp images, they also cast a layer of epoxy resin atop the mercury and used a crystal-controlled motor to keep the rotational speed constant.

A telescope needs more than a mirror. "[I] had been following Borra's work and I realized this could be a way to build a large, low-cost telescope for cosmological surveys" said Hickson.

To discover the large-scale structure of the universe Hickson needs to map the position and distance of millions of galaxies. Only a large telescope will allow him to see the faint galaxies to make this effort worthwhile.

Hickson's hobby is building and flying aircraft, which provided him the base of knowledge to use and shape composite materials like Kevlar and carbon fiber. He invented a lightweight, yet strong cell to hold the mercury.

In the event of a mercury-spilling cell breakage, Hickson dug a waist-deep, epoxy-lined concrete pit to contain the spill. To this floor was bolted one end of an aluminum tube hexapod.

At the other end, directly above the mirror, is attached a platform holding the CCD cameras and other instruments. This represents another cost-saving measure, since the massive piece of metal, called a telescope mount, is eliminated. Hickson noted: "We just throw the mount away."

A costly dome, which shelters many large observing telescopes, isn't required since LMTs only point straight up. At the UBC research forest, 60 miles (97 kilometers) east of Vancouver, British Columbia, Hickson built a ski-chalet-type, 4-story wooden building which uses a roll-off roof.

With the exception of the air bearing and other specialty items, the LMT was built by Hickson and his graduate students, or by tradesmen using locally purchased materials. The result was a professional-sized observatory with a cheap price tag.

Hickson's first LMT, built in 1993, was 106-inches (2.7-meters). It was intended to be a "proof-of-concept" instrument, but from the beginning the results were "about the same as a conventional glass-mirrored telescope" he said. This proved LMTs' astronomical worth.

It was dismantled two years ago to make way for its larger sibling. "We're taking it one step at a time. We know how to build 3-meter (118-inch) telescopes and we're now developing the technology to make larger ones," he said. The 6-meter starts operation later this year.

Hickson built a near twin of his first LMT for NASA in 1996. It scans low Earth orbit for space junk too small for ground-based radars to see. So far it is finding five times as much stuff as the radars see.

Just as many of us feel like we're not paid enough, many astronomers believe they never get enough time on a large telescope. With new observatories costing $100 million or more, there is no way an individual or a team of like-minded astronomers could hope to own one for their own use.

This leads to rationing. Even astronomers with the most exciting ideas must be satisfied to work with a state-of-the-art instrument like the Keck Observatory in Hawaii for no more than three or four nights a year.

This shortage is holding back cosmological research. Borra notes that in order to do meaningful work on the large-scale structure of the universe, one must pin down the location and distance of millions of galaxies.

Hickson explained he could tie up Palomar's 200-inch (5-meter) telescope for five years to do this survey. With astronomers lined up to use it, that is not going to happen. But with LMTs, the day of individual astronomers owning their own telescopes may have dawned.

"This is the beginning of an exploration into unexplored technology," said Hickson.