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The abbreviation HRS is used for high resolution spectrography, generally meaning using a spectrograph with a resolving power on the order of 100,000 or higher. (Such a threshold is likely to increase over time as higher resolutions become more common.) A motivation is radial velocity measurements. The abbreviation HDS (high dispersion spectroscopy) is used for the same meaning. High resolution spectrography might also be considered to include various spectrograph features and procedures that are used to achieve today's most precise radial-velocity measurements: these achieve results considerably beyond what is implied by the instrument's "raw", cited spectral resolution.
The exact abbreviation HRS is also used as the name for some such instruments, such as the Southern African Large Telescope (SALT)'s high resolution spectrograph or as part of the abbreviation for an instrument such as GHRS (the Goddard High Resolution Spectrograph) on HST. The abbreviation HDS is used for Subaru Telescope's high dispersion spectrograph.
The term low resolution spectrography (LRS, low resolution spectrograph) means the opposite, sometimes meaning anything not HRS, and sometimes assuming a middle ground between.