sentence2_structure: A telescope<>is used<>to make objects in space appear closer$$$A telescope<>to make<>objects in space appear closer$$$objects in space<>appear<>
sentence1: Four of these are used on two instruments, the UCSD Faint Object Spectrometer (FOS), and the Goddard High Resolution Spectrometer (GHRS), on the Hubble Space Telescope (HST).
sentence2: A telescope is used to make objects in space appear closer.
question: What instrument is used to make objects in space appear closer?