For months scientists, and others, have been speculating about bright spots which appeared on the dwarf planet Ceres as NASA’s Dawn spacecraft approached. Now that Dawn is a mere 14,000 miles above Ceres the bright spots have reappeared and despite the fact that they are clearly visible, nothing much has changed.

The leading theory remains that the spots are caused by water ice in craters on Ceres surface, but the images taken on April 14 and 15 from a point above Ceres’ north pole still do not allow any confirmation.

Despite the lack of closure on the question of the bright spots, other features of Ceres surface are now coming into focus including heavy cratering.

Dawn has now finished sending the images that NASA researchers need to maneuver the spacecraft into its “science orbit” in preparation for a more thorough examination of the largest object in the asteroid belt.

“All of the approach operations have executed flawlessly and kept Dawn on course and on schedule,” according to a statement from NASA.

Dawn will spend about three weeks in a almost circular orbit around Ceres at a distance of 8,400 miles starting on April 23. After that, starting on May 9, the spacecraft will begin to move into lower and lower orbits, improving the resolution of its photography as it goes.

“The approach imaging campaign has completed successfully by giving us a preliminary, tantalizing view of the world Dawn is about to start exploring in detail. It has allowed us to start asking some new and intriguing questions,” said Marc Rayman, Dawn’s mission director and chief engineer, based at NASA’s Jet Propulsion Laboratory, Pasadena, California.

The Dawn spacecraft is the first to orbit a dwarf planet, as well as the first to orbit two different targets. In 2011 and 2012, Dawn orbited the asteroid Vesta which is the second largest object in the asteroid belt. By orbiting both objects, data returned from Dawn will allow researchers to compare the two bodies using photographs and other data, gathered by the same instruments on the same spacecraft.

Researchers believe that both objects had the potential to become planets but their development was interrupted, probably by the gravitational influence of Jupiter.

Ceres, named for the Roman god of agriculture, was first discovered in 1772. Since that time however, relatively little has been learned about it. Even at its brightest, Ceres cannot be seen with the naked eye and it has been difficult to observe in any detail even with powerful telescopes.

In additions to the bright spots on the surface, researchers have many questions about the dwarf planet. There are indications that Ceres may have an atmosphere of some sort and water ice on the surface.

There are also indications that Ceres may have a subsurface ocean of liquid water. Although not considered a strong candidate for life, the combination of an atmosphere and underground ocean have caused some speculation about the possibility.

Any information Dawn can gather on Ceres will also help researchers when the New Horizons spacecraft arrives at the dwarf planet Pluto in July.