Some comets become famous by gracing the night skies for all to see, smudges of light with glorious tails streaming out behind them. Halley. Hyakutake. Hale-Bopp.

But one comet will go down in history as a true star, at least in the eyes of comet scientists. While comet Borrelly never shows off, never reveals itself to the naked eye, it now shines brightly in remarkable new images and other data obtained in a flurry of weekend observations by two spacecraft and several ground-based telescopes.

While Deep Space 1 was paying Borrelly a visit on Saturday, Sept. 22, the Earth-orbiting Hubble Space Telescope was also watching the comet, and multiple teams of researchers were taking its measure from the ground. The combined efforts provide views of the comet in several wavelengths of light, at multiple moments in time, far away and up close.

Borrelly is now the most observed comet in history, several scientists said, even though most people have never seen it. And researchers had a hard time overstating the importance of it all.

"It's mind-boggling and stupendous," said Laurence Soderblom, leader of Deep Space 1's imaging team.

But wait, there's more.

While Deep Space 1 snuck inside Borrelly's halo of gas and dust and saw its nucleus, two sets of observations in Arizona provided wider views of this halo, called a coma, as well as the comet's tail. Images from these observations also were released Tuesday. While not as visually stunning, they promise to add some fine detail to the picture of comets being painted by Deep Space 1's bold strokes.

University of Arizona astronomers Donald McCarthy Jr. and Humberto Campins used the university's 90-inch telescope at the Kitt Peak Observatory to study the comet in infrared light. They photographed the comet 12 hours before and 12 hours after NASA's Deep Space 1 spacecraft obtained close-up images of the nucleus.

And astronomers with the National Optical Astronomy Observatory (NOAO) employed their 84-inch telescope, also on Kitt Peak, to observe Borrelly in visible light.

"We are looking at the extended structure of the comet's dust coma and tail to help the NASA mission science team interpret their close-up images," said Beatrice Mueller, a research associate with NOAO.

Combining visible and infrared light helps astronomers see changes in the comet over hours and days.

"They [comets] can be completely unpredictable," Campins said. "Having simultaneous observations helps us determine what is happening with the comet at that moment. Both views give us a better look at the actual distribution of dust around the comet through time," Campins said.

In a telephone interview, Campins explained that the comet's coma shines because dust particles reflect sunlight. The way they reflect light -- in different wavelengths -- indicates the size and composition of the particles.

By studying these reflections in both visible and infrared light, scientists can narrow down what the dust is made of with even greater precision.

Campins said that the infrared observations of Borrelly are now also the best for any comet.

Harold Weaver, a Johns Hopkins University researcher, works with a team led by Alan Stern of the Southwest Research Institute that observed Borrelly from Hubble. Weaver has seen half of that data and said it looks promising.

Weaver said the comprehensive observations of Borrelly can now be compared with those of comet Halley, the only other comet that has been studied extensively from afar and up close.

Having extensive data on two comets "will help us understand the similarities and differences among cometary nuclei, especially when we throw in the indirect observations of cometary nuclei made by the Hubble Space Telescope and by ground-based thermal infrared observatories," he said.

And there is much to learn, as scientists now know.

One of the most puzzling early results of the Deep Space 1 observations is the curious way comet Borrelly interacts with space. As the comet nears the Sun, it is pummeled by charged particles that travel outward from the Sun. Two previous observations of this interaction in other comets showed that the solar wind flowed around the comets in a fairly symmetric fashion, much like water would flow around a smooth round rock.

But with Borrelly, that flow is bunched up on one side, researchers found.

"The center of this flow is not where the nucleus is, which according to conventional wisdom it should be," said David Young of the University of Michigan, leader of the team that made the measurements.

Something strange is going on, but only more research will explain what it is.

Meanwhile, now that Borrelly is a star, some backyard astronomers may want to find it. All that's needed is a small telescope (see map at top-right of this story).

"The comet is visible for us between 3:30 a.m. and 5:30 a.m., after the comet has risen on the horizon and before the sky gets too bright at dawn," Campins said of his Arizona location.