Yale University astronomer Debra Fischer says non-professional astronomers around the world are helping study the new information about the possible planets.

VOA: special.2011.02.09

Experts credit the Greek astronomer Archimedes with developing the earliest known device to show the daily movement of the planets.

VOA: special.2010.09.29

Others are from the mistaken science of Percival Lowell, the American astronomer who believed intelligent beings lived on Mars.

VOA: special.2010.07.28

Earlier,astronomer George Ellery Hale had offered Hubble a position at the Mount Wilson Observatory in southern California.

VOA: special.2009.04.29

The next Royal Astronomer, Edmund Halley, spent another forty years gathering information about the moon's orbit.

VOA: special.2010.07.14

An astronomer at Harvard College, Henrietta Leavitt, had discovered that these periods of brightness could be used to measure the star's distance from Earth.

VOA: special.2009.04.29

In the sixteenth century, one astronomer suggested that navigators could observe the moon as it passed in front of different known stars to tell longitude.

VOA: special.2010.07.14

A British astronomer named John Couch Adams had also predicted Neptune's position in space.

VOA: special.2011.07.27

In seventeen sixty-six, Royal Astronomer Nevil Maskelyne published the Nautical Almanac and Astronomical Ephemeris.

VOA: special.2010.07.14

Frank Marchis is an astronomer with the University of California at Berkeley.

VOA: special.2009.08.25

One astronomer said scientists have been filling in the details ever since.

VOA: special.2009.04.29

He had studied observations by the famous Italian astronomer Giovanni Schiaparelli.

VOA: special.2010.07.11

Royal Astronomer John Flamsteed worked at this task for forty years.

VOA: special.2010.07.14

Mark Reid is an astronomer with the Harvard-Smithsonian Center for Astrophysics.

VOA: special.2009.01.20

The astronomer would then check both photographs.

VOA: special.2010.07.11

Firefighters are also working to protect the century-old Mount Wilson Observatory, where astronomer Edwin Hubble made important discoveries in the 1920s.

VOA: standard.2009.09.01