urn:nasa:pds:context:telescope:lowell.21in0 1.2 1.22.0.0 Product_Context Lowell Obersvatory 21-in Reflector 2026-07-07 1.2 Removed duplicate Internal_Reference entries from Reference_List. 2025-01-07 1.1 Updated schema version. Adding missing "investigation" references. Adding missing "telescope" references. 2019-01-23 1.0 Initial version urn:nasa:pds:context:facility:observatory.lowell telescope_to_facility urn:nasa:pds:context:investigation:observing_campaign.lowell_uranus-neptune-photometry telescope_to_investigation 0.5334 248.335556 35.202778 2210 Geodetic - North American (1927) Datum 21.0-in (53 cm) reflector telescope at Lowell Observatory, Mars Hill, Flagstaff, AZ, was built for Harold Johnson, in 1953. The telescope ushered in photoelectric astronomy at Lowell. The 21-in is the only manually slewed telescope at Lowell and is still in use with minimal upgrades since 1953.