urn:nasa:pds:context:instrument:kpno-mcmath-pierce-solar.main_1m61.vacuum-spectrograph 1.0 1.13.0.0 Product_Context 2020-08-03 1.0 Initial creation of the context product. Information from websites: https://www.nso.edu/telescopes/legacy-telescopes-2/ and https://www.noao.edu/kpno/ urn:nasa:pds:context:telescope:kpno-mcmath-pierce-solar.main_1m61 instrument_to_telescope Vacuum Spectrograph Spectrometer The third mirror of the McMath-Pierce main telescope sends light down into the observing room can be moved above three different positions. Two of these have a vacuum spectrograph beneath them, one of 18 meter deep and the other 4 meter deep with lower resolution but higher light throughput. These two spectrographs are able to rotate to compensate for the rotation of the image caused by the use of a heliostat. The third position can only be equipped with a static optical table with no image rotation correction and is therefore rarely used.