Venus Hemispherical Globes (with place names)
The images used for the base of this globe show the northern and southern hemispheres of Venus as revealed by more than a decade of radar investigations culminating in the 1990-1994 Magellan mission. The Magellan spacecraft imaged more than 98% of Venus at a resolution of about 100 meters; the effective resolution of these images is about 3 kilometers. A mosaic of the Magellan images (most with illumination from the west) forms the image base. Gaps in the Magellan coverage were filled with images from Soviet Venera 15 and 16 spacecraft in the northern quarter of the planet, with images from the Earth-based Arecibo radar in a region centered roughly on 0 degrees latitude and 0 degrees longitude, and with a neutral tone elsewhere (primarily near the south pole). The composite image was processed to improve contrast and to emphasize small features and was color-coded to represent elevation. Gaps in the elevation data from the Magellan radar altimeter were filled with altimetry from the Venera spacecraft and the U.S. Pioneer Venus missions.
The images are presented in a projection that portrays the entire surface of Venus in a manner suitable for the production of a globe. A specialized program was used to create the "flower petal" appearance of the images; the area of each petal from 0 to 75 degrees latitude is in the Transverse Mercator projection, and the area from 75 to 90 degrees latitude is in the Lambert Azimuthal Equal-Area projection. The projections for adjacent petals overlap by 2 degrees of longitude, so that some features are shown twice. Names are approved by the International Astronomical Union. (See PIA03151 for the image without place names.)