For wavelengths longer than 6300 Angstroms, the free spectral range of HIRES echelle orders exceeds the width of the detector. In addition, the HIRES detector is a three chip mosaic, meaning there are two interchip gaps that can reduce spectral coverage. To aid observers in optimizing spectral coverage via variation of echelle and cross disperser angles, an echelle format simulator (EFS) is provided.

In the past, the EFS was provided for download. With the upgrade of the HIRES detector in mid-2004, a new simulator was required. Problems encountered with upgrading the old version, combined with the increasing difficulty in supporting its use on evolving platforms has lead us to decide to offer a web based EFS instead. Two versions are needed, one each for the blue and red cross dispersers^[1].

The new EFS's are available below. Many features of the old simulators are not built in yet and we welcome your requests. We will attempt to add new features in order of popularity. Please note that these are test versions and grating angles should be checked with the old style simulator installed at Keck.

EFS version 0.9
README for version 0.9.

Legacy versions of the HIRES EFS can be found here.

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