Double light source Ronchi Tester for detection of ruling rotations

Abstract

In this work, a modified Ronchi tester with a double light source has been
implemented for evaluating and minimizing the rotation angle of the Ronchi ruling.
The ruling rotations produced by positioning errors can become very small and could
be going unnoticed (0.1◦), however we have demonstrated that for these angle sizes
the aberrations in the wavefront can not be completely neglicted. Accordingly with
a rotatory mechanical device for correctioning the Ronchi ruling has been also added
with this proposals. With our aim, in spite of non-straight shape that the ronchigrams
can present in the patterns, the process of the ruling rotation degree measuring has
hurled some experimental results when three concave mirrors: a concave spherical
mirror, a concave parabolic mirror (the primary mirror of a Newtonian telescope) and
a spherical concave mirror (the primary mirror of a Maksutov-Cassegrain telescope)
have been tested.