The "Instrument Selector" is essentially a new fold mirror that has been installed in the "acquisition boxes" of both SpUpNIC and HiPPO<ref>''22 Feb 2024: the implementation of the fold mirror in HiPPo's acquisition box has not been completed at time of writing</ref> that allows the observer to switch between two instruments: a "primary" and a "secondary" instrument where the primary instrument is either SpUpNIC or HiPPo and the secondary instrument is always a new SHOC system. In other words, a SHOC is from now on permanently available on the 74-inch.
Figure 1 ('''still need to add figure''') shows how the new SHOC system is mounted to the side of SpUpNIC's acquisition box. The new fold mirror that acts as the "Instrument Selector" is shown in the top panel and actuates IN/OUT of the science beam above the "guider mirror". The new SHOC system replaces the old guider box that use to migrate between SpUpNIC and HiPPo. The new SHOC system is incorporated into a newly designed off-axis "pick-off" style guider system that can accommodate a filter wheel unit and SHOC camera behind the guider. The new SHOC system also has a focal reducer built in providing just over double the FoV-width compared to the the old system (2.7' × 2.7' for the new system vs. 1.3' × 1.3' for the old setup).
[[File:Instrument_selector.png|left|thumb|300px800px|Figure1: Instrument Selector Concept and new SHOC system mounted to the side of SpUpNIC's "acquisition box"]]