Prelude to retrograde;a post about the first planet

Mercury will go retrograde in a little less than 24 hours.
Here's an item that I just read about the innermost planet.

"Astronomers at the University of North Carolina have published a new map of the surface of Mercury, containing features previously unseen. Their map is based a technique familiar to amateur planetary imagers: 'lucky imaging.' That is, using a webcam to obtain crisp frames...

"[Cecil and Rashkeev] specifically targeted part of the hemisphere not mapped by the Mariner 10 spacecraft three decades ago. On the mornings of March 23rd and April 1st, 2007, the team managed to record more than 30,000 frames around sunrise. After software picked out the best frames, the final stack of the sharpest images achieved an angular resolution of 0.2 arcseconds. Their results appear in the October issue of the Astronomical Journal.

"Although NASA's Messenger spacecraft is due to make its first flyby of the elusive planet in January 2008, results like these can help discover regions of particular interest. Already, the team's new map shows bright splotches thought to be fresh craters 15 to 150 km across, as well as darker regions at mid-latitudes associated with ancient lava flows."