System and method for telescope guiding utilizing an artificial reference star

A system for controlling the positioning of a main telescope having an associated guide scope through which a guide star is selected, comprising:

• a point source of light located in the vicinity of the imaging means within said main telescope;
• a means for directing the light from said point source outside of said main telescope via its aperture, said light from said point source exiting said aperture being an output beam;
• a retroreflector which retroreflects said output beam at the same direction angle of the beam exiting the aperture into said guide scope such that an artificial reference star is created in said guide scope's field-of-view that is locked to the line of sight of said imaging means, said guide scope having an associated focal plane on which said artificial and guide stars are focused;
• and
• a means for varying said line of sight such that the positional displacement between said selected guide star and said artificial star on said guide scope's focal plane is maintained approximately constant.