RESUMO
The technique of using magnetic-tape recorders and atomic frequency standards to operate two widely separated radio telescopes as a phase-coherent interferometer when the stations have no radio-frequency connecting link has been successfully tested at the National Research Council of Canada's Algonquin Radio Observatory.
RESUMO
A three-mirror rotationally symmetric telescope has been designed in which the secondary and tertiary mirrors are behind the primary. In this configuration the mounting structure of the secondaries need not interrupt the light path, thus avoiding the production of undersirable diffraction sidelobes. In a 1° total field of view the image blur circle is less than 3 arcmin. The design has application in the millimeter and submillimeter wavelength regions for problems in which low response to far-off-axis sources is critical.
RESUMO
An optical condensing system is described that consists of a lens and the polished interior of a cone generated by rotating a hyperbola about an appropriate axis. An optimum concentration of light is achieved in a relatively compact system. In certain circumstances the hyperbola reduces to a straight line, simplifying the construction of the cone.