0 a slight backwards and forwards movement of something, especially of planets etc. in the sky:
lunar libration
Ignoring the likely functionally uninteresting bond vibrations, the very shortest times are the fundamental group librations and rotations of methyl groups, which typically occur in the picosecond range.
This can be simplified further by recognizing that local bond librations and other motions are likely to occur on very different timescales, and thus their averages can be computed independently.
The visibility of this formation is affected by libration, and even under favorable conditions it is highly foreshortened.
At this location the crater appears much foreshortened and can only be observed during favorable librations.
As a result, spacecraft in libration point orbits must use their propulsion systems to perform orbital station-keeping.
That is, the features that would produce a contour effect along the limb due to libration.
It was the first artificial object placed at a so-called libration point, proving that such a suspension between gravitational fields was possible.
It can also become hidden from sight due to libration, or brought into a more favorably viewing position.
