urn:nasa:pds:context:investigation:individual.arecibo_radar_imaging_and_doppler_spectroscopy 1.0 1.18.0.0 Product_Context 2024-02-07 1.0 Initial version urn:nasa:pds:context:facility:observatory.arecibo investigation_to_facility Arecibo Radar Imaging and Doppler Spectroscopy Individual Investigation 1963 2020 The Arecibo Observatory Planetary Radar system was used to observe asteroids and planetary surfaces with its 12.6 cm (2380 MHz) and 70-cm (430 MHz) radar systems from 1963 to 2020. This investigation provides processed data from Doppler-only spectroscopy and delay-Doppler imaging of those bodies. Most of the data in this investigation was of small bodies, but data from other targets (planets and moons) are also included. Most of the data are from after the "Gregorian Upgrade" of the telescope in the late 1990s, as earlier data were rarely preserved due to data volume and loss of knowledge of the organization of the data.