Astronomers trying to peer into the heavens from huge ground-based telescopes measure success in relation to the Hubble Space Telescope, which suffers no turbulent air but is limited by its relatively small size.

To compete with Hubble, surface telescopes are now being outfitted with adaptive optics systems, which read the atmosphere's instability and adjust mirrors rapidly during the course of an observation session.

This picture from a new near-infrared camera on southern Arizona's 6.5-meter (21-foot) MMT Observatory, run by the University of Arizona and the Smithsonian, was released last week. Researchers involved in the observation said it is about three times sharper than could be obtained by Hubble's infrared camera.

The photograph is of a planetary nebula known as IC 2149. It's a cloud of gas and dust shed from a dying star 3,600 light-years away and 1.5 trillion miles (2.5 trillion kilometers) across. Planetary nebulas are so-named because in early telescopes, they appeared as smudges in the sky not unlike the outer planets of our solar system.

"What you are seeing here is a star, a little less massive than the sun, that has used up all the fuel at its nuclear-burning core," said University of Arizona graduate student Patrick Young. "Unable to produce energy, the core starts to contract, and turns into a ball of carbon and oxygen the size of the Earth. This gravitational contraction releases a lot of energy, and that causes the star to shed its outer atmosphere. The material we are actually seeing in the picture is the gas and dust being lit up by the light from the central star."

Astronomers were pleased to see faint detail very near the bright star. The picture reveals a mixture of gas and dust several thousand times dimmer than the star itself, they said.

Credit: UA, Patrick Young, Donald McCarthy, Craig Kulesa, Karen Knierman, Jacqueline Monkiewicz (Steward Observatory), Guido Brusa, Douglas Miller, Matthew Kenworthy (Center for Astronomical Adaptive Optics)