Our objective is a wide-field spectroscopic survey telescope with simultaneous operation of a large field-of-view, high multiplex MOS, including both medium-and high-resolution modes, and a giant panoramic central IFS. In addition, our conceptual design for WST will allow for the possibility of technical upgrades to enhance the scientific information in the planned surveys (e.g.,by extension to IR) or to address new potential science missions.
These ambitious requirements will place the WST MOS and IFS capabilities far ahead of the existing or planned competing facilities. Using for example, the primary mirror collecting area and the fibre multiplex gain as a measure of the survey speed, WST MOS is faster by a factor 60 than PFS@Subaru and by a factors of 17 and 3 compared to the proposed MSE and Megamapper facilities, respectively. Using the etendue2 metric to perform a similar comparison for the WST IFS, it will be 17 and 142 times faster than MUSE@VLT and KCWI@Keck respectively.