Lunar Section        


Lunar Selected Areas Project


The percentage of sunlight reflected by the surface of the Moon varies as the phase angle changes throughout the lunar month. Taken a step further, observers are well aware that one area of the Moon reflects more light (e.g., a crater rim or central peak) than another region (e.g., the maria), regardless of the phase angle. These areas, in turn, also vary in appearance as the illumination changes. These differences in tone are generally more conspicuous at Full Moon, and the investigation of light and dark areas of the Moon is an interesting observational endeavor.

While there is a definite requirement to know how various lunar features change their normal appearance throughout a lunation in response to variations in phase angle, even more intriguing are those lunar features that behave in an unusual, sometimes unpredictable, and non-repeating manner as solar illumination changes. The A.L.P.O. Lunar Selected Areas Program (SAP) is chiefly concerned with systematically monitoring regular and cyclical long-term variations during many lunations of specifically designated, or “selected”, areas on the Moon. In general, the SAP is designed to intensively study and document for each of these features the normal albedo changes in response to conditions of varying solar illumination.

For additional information see: Program Overview

Selected Areas Program Observing Documents:

SAP Handbook
Topographical Studies Digital Image Submission Form
Crater Drawing Outline Chart
Albedo & Supporting Data for Crater Drawings
Assigned Albedo Index Points (1)
Assigned Albedo Index Points (2)
Dark Haloed Crater Visual Data Submission Form

   Powered by WordPress     Personalized by: Larry Owens     Contact the Webmaster