Interferometric resolution boosting for spectrographs

David J. Erskine; Jerry Edelstein

doi:10.1117/12.549947

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30 September 2004 Interferometric resolution boosting for spectrographs

David J. Erskine, Jerry Edelstein

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Proceedings Volume 5492, Ground-based Instrumentation for Astronomy; (2004) https://doi.org/10.1117/12.549947
Event: SPIE Astronomical Telescopes + Instrumentation, 2004, Glasgow, United Kingdom

Abstract

Externally dispersed interferometry (EDI) is a technique for enhancing the performance of spectrographs for wide bandwidth high resolution spectroscopy and Doppler radial velocimetry. By placing a small angle-independent interferometer near the slit of a spectrograph, periodic fiducials are embedded on the recorded spectrum. The multiplication of the stellar spectrum times the sinusoidal fiducial net creates a moire pattern, which manifests high detailed spectral information heterodyned down to detectably low spatial frequencies. The latter can more accurately survive the blurring, distortions and CCD Nyquist limitations of the spectrograph. Hence lower resolution spectrographs can be used to perform high resolution spectroscopy and radial velocimetry. Previous demonstrations of ~2.5x resolution boost used an interferometer having a single fixed delay. We report new data indicating ~6x Gaussian resolution boost (140,000 from a spectrograph with 25,000 native resolving power), taken by using multiple exposures at widely different interferometer delays.

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David J. Erskine and Jerry Edelstein "Interferometric resolution boosting for spectrographs", Proc. SPIE 5492, Ground-based Instrumentation for Astronomy, (30 September 2004); https://doi.org/10.1117/12.549947

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