Moon's surface (horizontal) is moving to the left. Light waves of a star are coming from the upper left. Coming direction of light waves (measured with an interferometer [such as VLT, VLBI] set on the moon) will not be changeable by moon's motion (principle of interferometer [illustrated by two telescopes and right triangle] seems to guarantees it). On the other hand, because of aberration, apparent position (of this star) will be changeable. If this difference is true, secular aberration seems to be measurable.
- Correction - Angle of annual aberration is a 20seconds angle. Angle distinguished by VLBI is below a milliseconds angle.
Moon's surface (horizontal) is moving to the left. Light waves of a star are coming from the upper left. There is an interferometer (small-sized VLT) on the moon's surface. When it is leaned, it will be possible to know the true coming direction of light waves (independently of moon's motion). On the other hand, because of aberration, apparent position (of this star) is changeable. If this difference is true, secular aberration seems to be disclosed.
Imagine motion of stars (seen from horizontal coordinate system) caused by earth's rotation. Secular aberration will be detectable (reason ; earth's axis will not overlap with the direction of motion of solar system).-P.S.- In a web-site (in Japanese), i found value 13.4 seconds of arc (it's value of secular aberration). Surprising !!
Above value "13.4 seconds of arc" is shown in a report carried in a journal "Report of the national astronomical observatory of Japan ; Feb 1993". No book seems to touch on this value.
Two disks are rotating (in outer space ; in non-gravitational field ; horizontally). Rotating speed of one disk is 10 rotations per second and that of the other disk is 20. A body is detached from the edge of disk and is receding along a tangent line (and every tangent line does not rotate relative to space). It will be the same about a photon (emitted from a rotating source).
