Lunar Clair-obscur Effects – French for “light” (clair) and “shadow” (obscur)

Some fantastic images showing two ‘Clair-obscur’ effects visible on the surface of the Moon taken by member Jim Burchell on the 19th & 20th January 2024.

 

Clair-obscur effects are revealed when light and shadow interact with the Moon’s craters and other features to trick the eye into seeing something that isn’t really there.  Below are 7 of the best recognisable shapes created on the surface of the Moon.

 

Most Clair-obscur effects require specific timing. Some last for days and are easy to see. Others last for a few hours and are more challenging.  Clair-obscur effects on the Moon are not one-time or rare events; this is because lunar lighting patterns repeat in a cycle of approximately 29.5 days, so each effect can be observed from somewhere on Earth once every month.

 

All of Jim’s images below were a single shot; taken with a Pentax KP body attached to 102mm Altair Astro refractor. The images where then processed in Snapseed.

 

 

 

For more information about Clair-obscur effects check out: