The insensitivity and personal equation errors of optical settings

Abstract

The paper contains the results of observations on the insensitivity, that is, mean difference of the individual observations of a large series from the mean of the series, in the case of X type graticules set on vertical object lines. The influence of the following factors was investigated: Thickness of cross-wires. Angle between cross-wires. Field brightness. Pupillary aperture. Observations were also made of the magnitude of the personal equation error in such settings.