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A high-resolution spectrograph (HRS) is taking shape for the Hobby-Eberly Telescope (HET). HRS will be mounted on a Newport bench in an insulated chamber in the 'basement' of the HET building, internal to the pier, and will be linked to the corrected prime focus of the HET through its Fiber Instrument Feed. Spectra will be recorded on a 4096 X 4096 Orbit CCD mosaic at resolving powers of 30,000 to 120,000, using a mosaic of two R-4 echelle gratings replicated on a single blank at Spectronic Instruments and a selection of two cross- dispersing gratings. This paper will describe the design and report on the current construction status, and will describe innovative aspects, in particular a new all-refractive camera designed by Epps. The HRS design incorporates Barranne's white-pupil concept as adapted for ESO's VLT by Delabre and Dekker. Predicted performance from ray-trace analysis will be demonstrated. With the 316-gr/mm cross-dispenser the full 420 - 1,100 nm spectral range can be recorded in two exposures at any resolving power up to 120,000. Greater order separation can be had with the 600-gr/mm grating, requiring four exposures if the full range is needed. Designed for remote, queue-scheduled operation, HRS will be capable of rapid response to discoveries of transient phenomena. It will be directed toward discoveries of extra-solar planetary systems and studies of long-period variable stars and absorption line systems in QSOs as well as stellar nucleosynthesis and chemical compositions.© (1998) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only. |
