Bob Moler's Ephemeris Blog

Ephemeris for Arbor Day, Friday, April 24th.  Today the Sun will be up for 13 hours and 54 minutes, setting at 8:38.   The Moon, 1 day before first quarter, will set at 2:26 tomorrow morning.  Tomorrow the Sun will rise at 6:42.

The Dawn spacecraft with its ion engine is descending into orbit of that other dwarf planet Ceres, the largest body in the asteroid belt.  Over the past month Dawn has been maneuvering over Ceres’ night side to descend into a polar orbit to better survey the planet.   Last week the Jet Propulsion Laboratory team that has been operating the spacecraft released a video of several photographs of Ceres’ pole as it rotated.  It was still a crescent view, but soon we’ll see Ceres up close and very personal.  We’ll get a closer look at those enigmatic white spots.  Are they just white ice patches on the surface, or are they ice cryovolcanoes spewing water, or something else?  Stay tuned.

Times are for the Traverse City/Interlochen area of Michigan.  They may be different for your location.

Addendum

Ceres animation from April 14-15, 2015. Dawn was 14,000 miles (22,000 km) from Ceres. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.  Click the image to enlarge.

This is a newer animation than the one mentioned in the transcript above that was actually written on the 19th.  Here’s a link to the NASA page that describes the image.  It also has a link to an enlarged frame containing the double bright spot.

This is a processed still image of Ceres from the above animated sequence of images.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

There’s no help figuring out what they are but the smaller spot is resolved into two spots.  The bright one is still unresolved.  As of yesterday the Dawn spacecraft should be in its first circular orbit of Ceres at an altitude of  8,400 miles (13,500 km) from Ceres for a few weeks before descending to a lower orbit of Ceres the starting the first week in May.