This month, binocular and small telescope observers of Colorado skies will have a unique opportunity to observe a peripheral player in the ongoing controversy over the status of the outer solar system world known as Pluto.

On New Year's night in 1801, an Italian astronomer named Giuseppi Piazza stumbled across an object that changed its position nightly against the backdrop of fixed stars. After months of observations and an ingenious orbital analysis, it was determined that the object was a member of the solar system and moved in an orbit about the sun halfway between the orbits of Mars and Jupiter.

Piazzi's discovery was named Ceres for the Roman goddess of agriculture and the patron of Sicily. It was hailed as the missing planet that was presumed to exist in what was then regarded as a suspiciously wide gap between Mars and Jupiter.

Ceres' status as a full-fledged planet was almost immediately diminished with the discovery in 1802 of an orbitally similar object called Pallas, followed by the discoveries of Juno in 1804 and Vesta in 1807. By 1850, more than a dozen of these "planets" had been discovered and the astronomical texts of the day dutifully incorporated each of these objects into discussions of the sun's family of planets.

All of this prompted astronomers in 1853 to define a new class of celestial objects - the asteroids. The term asteroid is derived from the Greek word meaning "star-like," owing to the fact that the telescopes of the day could not detect anything but a star-like, unresolved shape for these objects. In the past century and a half, thousands of additional asteroids have been discovered orbiting in this same region of the solar system. As a result, this vast debris field has come to be known as the asteroid belt.

So matters rested until the recent controversy over the status of Pluto erupted onto the public scene. Like Ceres, Pluto was for decades accorded all of the rights and privileges of a planet. Unfortunately, Pluto's planetary status has also experienced a downfall similar to that of Ceres, owing primarily to the discovery over the past two decades that Pluto is embedded in a region of small, snowball-like objects called the Kuiper Belt.

At least one of these Kuiper Belt objects, named Eris, is actually larger than Pluto.

In an attempt to retain at least some sense of Pluto's planetary respectability, astronomers are now defining Pluto as a dwarf planet, complete with a well-defined set of observable characteristics for such objects. Pluto's loss in this matter turns out to be Ceres' gain, as the latter object also satisfies the defined characteristics of a dwarf planet. Ceres has, to date, bounced from planet to asteroid to dwarf planet as astronomers continue their struggle to formally and unambiguously define and categorize the various objects found in the solar system.

During March, Ceres will be closer to the Earth than at any time until the year 4164. Even so, the brightness of this 550-mile-wide sphere hovers only just below naked eye visibility. But Ceres can be readily detected in binoculars or a small telescope as this planet/asteroid/dwarf planet arcs over the back of the constellation of Leo about halfway between Leo's sickle-shaped head and his triangular-shaped haunches. Observations made on a night-to-night basis will quickly reveal Ceres' moving presence, just as it did to Piazzi more than two centuries ago.

Elsewhere in the sky

> After spending several months in the evening sky, the dazzling planet Venus drops into the western solar glare over the next three weeks. This beauteous planet now gleams for three hours after sunset. By the third week in March, it will be setting barely an hour behind the sun. After passing between the Earth and the sun on March 27, Venus quickly reappears in the morning sky at the end of the month and will remain as a prominent object in the predawn sky for the rest of the year.

> Saturn reaches opposition to the sun on March 8, when the Ringed Planet will rise at sunset, set at sunrise and be visible all night long as a golden object in southeastern Leo. Saturn's famed ring system is now in a nearly edge-on orientation, thus allowing a much better telescopic view of the brightest of Saturn's many satellites.

> Jupiter moves into the predawn twilight this month and can be seen just above the southeastern horizon about 45 minutes before sunrise.