Arecibo Radar Maps of Venus from 1988 to 2020

Abstract Over its 57 yr history, the Arecibo telescope was used to produce radar maps of Venus that pioneered our understanding of surface landforms and geologic processes. The best spatial resolution of 1–2 km achievable with the S-band (2380 MHz) transmitter was first used to map the surface in 1988, providing dual-circular polarization images ahead of the Magellan mission. Along with the 1988 observations, high-resolution images from observing runs in 2012, 2015, 2017, and 2020 have been archived with the NASA Planetary Data System to preserve these legacy data sets. We document the data collection and processing methods for the Arecibo Venus data, discuss unique aspects of the delay-Doppler imaging, and derive relative calibration factors linking the final multilook maps and Magellan data. The observations also allow for derivation of the circular polarization ratio and, potentially, the Stokes vector components. These results are particularly relevant for long-term monitoring of the spin rate, surface change detection, and planning for S-band polarimetry from the EnVision orbiter mission.