Multiple Object Fiber Optics Spectrograph Feed For The Hale Telescope

Abstract

A preliminary design of a fiber-optics feed for the prime-focus spectrograph of the Hale telescope using computer controlled movable fiber has been completed and a test of a proto-type configuration carried out. The complete design will divide a 76mm square field into 10 strips and will place two movable fibers in each strip. The fiber pickups, which are moved by stepper-motor driven lead screws, may be placed anywhere in the strip subject to the limitation that they not pass each other. The prototype consisted of a single strip with two fibers operated with manual input to the stepper motors. In tests performed at the 5 meter Hale telescope in April of 1981 spec-tra of two bright 0 stars (B = 8.5 mag) separated by 5 arc minutes were photographed with a 3 minute exposure using a 1200 line/mm grating and unbaked 103a0 plates. The performance of the prototype configuration was within a factor of two of the unmodified prime-focus spec-trograph indicating a potential for a ten-fold increase in the effective utilization of the telescope for spectrographic survey work when fitted with the 20-fiber feed.

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