The use of a pair of prisms to achieve precise pointing of an optical axis is analyzed. A sextant using prism pairs having an accuracy of 0.2″ is comfortably within the present state of the art. Even higher accuracies can be achieved at the expense of a limited maximum range in the sextant.

1.
It is supposed here that the necessary platform motion can be accomplished with two degrees of freedom. The axis of such a platform cannot be conveniently adjusted when it lies in some solid angle close to a particular direction, and the sextant could not operate in this solid angle. If necessary, this restriction can be removed by introducing an additional degree of freedom into the platform motion.
2.
M. Born and E. Wolf, Principles of Optics (Pergamon Press, Inc., New York, 1959), p. 210.
This content is only available via PDF.
© 1965 The American Institute of Physics.
1965
The American Institute of Physics
You do not currently have access to this content.