Verification on supporting points of line standard(I)

Bessel point

Abstract

The Bessel supporting point is recommended for line standard of length measurement. The point is used to realize precise length measurement with the ratio of l/L= 0.5594, that is, supporting length l to a whole length L and to minimize the deformation length of line standard. However, the theoretical analysis of the point is not clarified. The point for line standard is verified in this report, based on mechanics of materials. As an example of the point, the length change value of the prototype meter (Mètre-étalon) used before is calculated and obtained -0.8 nm as a result.