0 a slight backwards and forwards movement of something, especially of planets etc. in the sky: --
lunar libration
It can also become hidden from sight due to the effects of libration.
Other observations suggest they move around the libration points in ellipses of about 6 by 2 degrees.
In addition, to the extent that tides produce heat along fractures libration may affect the magnitude and distribution of such tidal shear heating.
The study was conducted inside the interval where libration happens.
It lies just beyond the western limb, at the far edge of the region that is brought into view during favorable librations.
Due to its proximity to the western lunar limb, this area of the surface is occasionally visible during favorable librations.
In this location the vicinity of the crater can be viewed during favorable librations, although it is viewed from on edge.
It can also become hidden from sight due to libration, or brought into a more favorably viewing position.
