The High Dispersion Spectrograph (HDS), which is located at the Optical Nasmyth platform, provides optical spectroscopy in the range 3 000 - 10 000 Angstroms, with a spectral resolution of up to 160 000; this is the highest resolution of any optical spectrograph on an 8-10m class telescope.

Incoming light is reflected from the slit into a slit viewing camera, while that which passes through the slit is collimated into a 272 mm-diameter beam and dispersed with an 31.6 lines/mm echelle blazed at 71.3 degrees. The light then passes to the cross-disperser, before being focused onto the detector - a 2x1 mosaic of EEV CCDs. One of the cross-dispersers - one for the blue region (400 lines/mm, blazed at 4150A) and one for the red region (250 lines/mm, blazed at 7000A) - is selected according to the user's choice.

The 13.5um pixel size provides a maximum (2-pixel FWHM) resolution of 160 000 (1.8 km/s), which can be achieved with a 0.2'' slit or Image Slicer#3.

Inside of HDS spectrograph room

Subaru HDS OPE file Editor is now available to download for UNIX, Windows, and mac OS. You can use it for your obs. preparation by yourself. Please see this page for more detail.

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Outside Link


When referring to HDS in a paper, please use the following citation.

Further information

Questions regarding HDS should be directed to Akira Arai (arai__at__naoj.org).

26 Jan 2022

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