urn:nasa:pds:context:telescope:mcdonald.struve2m1 1.4 1.22.0.0 Product_Context 2.1-m Struve Warner & Swasey reflector 2026-07-07 1.4 Removed duplicate Internal_Reference entries from Reference_List. 2025-01-07 1.3 Updated schema version. 2023-02-01 1.2 Added lid_ref to instrument cs 2021-12-07 1.1 Added lid_ref to instrument molp 2016-03-03 1.0 Initial version exported from OLAF urn:nasa:pds:context:facility:observatory.mcdonald telescope_to_facility urn:nasa:pds:context:instrument:mcdonald.harlanjsmith_2m7.p45a_phot telescope_to_instrument urn:nasa:pds:context:instrument:mcdonald.struve2m1.molp telescope_to_instrument urn:nasa:pds:context:instrument:mcdonald.struve2m1.cs telescope_to_instrument 2.1 255.977745 30.671583 2069 Unknown The 2.1-meter Struve Warner & Swasey reflector, commonly known as the Otto Struve Telescope, is a historic optical telescope located at McDonald Observatory in the Davis Mountains of West Texas. Commissioned in 1939 and named in honor of astronomer Otto Struve in 1966, it was the largest telescope in Texas and one of the largest in the world at the time. Designed by the Warner & Swasey Company, the telescope features an 82-inch (2.1-meter) mirror and was instrumental in the development of the Johnson-Morgan UBV photometric system. Notably, in 1949, astronomer Gerard Kuiper discovered Neptune's moon Nereid using this telescope. Despite its age, the Otto Struve Telescope remains operational, celebrating its 85th year of service in May 2024 .