As NASA’s Dawn spacecraft nears the dwarf planet Ceres, it continues to send back more detailed photos of the mysterious Occator crater, which appears as a luminous bright spot from afar. According to a report from NBC News, scientists have hypothesized that the spots could be salt deposits, or even ice.

Dawn team members created the new image of the Occator crater by overlaying an exposure of the bright spots onto a normal photo of the surrounding landscape. The result is a view of Ceres as a whole, with the crater illuminated.

The two photos were taken as Dawn hovered just 915 miles over the surface of Ceres, offering the closest look at the dwarf planet yet. The crater is 60 miles across and two miles deep.

Dawn will continue to approach Ceres as October nears, when the ship will enter its last orbit roughly 230 miles above the surface. The craft first entered Ceres’ orbit on March 6, 2015.

According to Marc Rayman, the chief engineer of the Dawn mission at NASA, explains that the resolution on the photos taken by the spacecraft is unprecedented, and illuminates the tiniest variances in surface topography.

Researchers will soon be able to analyze the geological structure and the underlying chemistry on the dwarf planet.