Occultation of Mars
January 13, 2025

 One of the first observational treats of the year 2025 is a prime seat for those of us in North America of the full Moon occulting the almost at opposition planet Mars in the mid-evening.  We were also lucky to have nearly perfect weather in central Virginia ~ totally clear skies but no wind and temperatures in the mid to high 30's.
 
My set-up for this event was a 1970's vintage Celestron C8 telescope with a 20 mm Erfle eyepiece yielding 100x, and then at the end switching to a Meade research grade 12.4 mm Erfle eyepiece for 161x.  All the pictures were made by holding my iPhone 8 up to the eyepiece for afocal shots.   The views of the event through the telescope were impressive, in great part because the seeing was good enough to be able to make out the north polar cap on Mars as well as the dark markings of Mare Acidalium just below the polar cap, and the dark areas of Sinus Meridiani, Mare Erythraeum, and Solis Lacus on the southern limb.
 
  According to a google search, the Moon's albedo is 0.12, whereas the albedo of Mars is 0.17.  I could not detect a significant difference in the surface brightness of the two bodies, and in fact I would say that they appeared to be very similar as the Moon approached Mars ~ maybe the difference is that the Moon's albedo must be an average of the reflectivity of the bright highland areas and the darker mare regions.  As the two grew closer, it was Mars being juxtoposed against a brighter, whiter region of the Moon.  The actual occultation took less than a minute, at least that's the way it seemed to me.
 
The main features on the Moon that we are seeing approach Mars are the famous ray crater Tycho on the right side of the pictures, and left of the center of the Moon are the ray craters Copernicus and Kepler (top and bottom, respectively).  Between Tycho on the right and Copernicus and Kepler on the left are the two smaller mare, Nubium above and Humorum below.  The large dark area below and to the left of Copernicus / Kepler is Oceanus Procellarum.  The bright spot to the lower left of Kepler is Aristarchus.