Lunar limb
The lunar limb is the edge of the visible surface (disc) of the Moon as viewed from Earth.[1] Seen from afar, it looks like a circular arc, but with higher resolution, we can see that the Moon’s surface is not flat and therefore its profile is irregular.
The lunar limb is not always the same: because of the
collimated rays of sunlight that shine through in some places while not in others during a solar eclipse
.
The contrast of the bright lunar disc against a black night sky makes the lunar limb a popular target when testing telescope optics (including binoculars).
References
- ^ "List of basic lunar features". Archived from the original on 2006-02-03.
- ^ O'Byrne, Chris. "Lunar Limb Corrections". Archived from the original on 2008-01-13.
- Bibcode:1963USNAO..17....1W.