High-Resolution Ceres HAMO Atlas derived from Dawn-FC images

Abstract

Introduction: NASA’s Dawn spacecraft will orbit the dwarf planet Ceres in August and September 2015 in HAMO (High Altitude Mapping Orbit) with an altitude of about 1,500 km to characterize for instance the geology, topography, and shape of Ceres before it will be transferred to the lowest orbit. One of the major goals of this mission phase is the global mapping of Ceres. Data: The Dawn mission is equipped with a fram-ing camera (FC). The framing camera will take about 2600 clear filter images with a resolution of about 120 m/pixel and different viewing angles and different illumination conditions. Data Processing: The first step of the processing chain towards the cartographic products is to ortho-rectify the images to the proper scale and map projec-tion type. This process requires detailed information of the Dawn orbit and attitude data and of the topography of the target. Both, improved orientation and high-resolution shape models, are provided by stereo processing of the HAMO dataset. Ceres' HAMO shape model is used for the calculation of the ray intersection points while the map projection itself will be done onto a reference sphere for Ceres. The final step is the controlled mosaicking of all nadir images to a global mosaic of Ceres, the so called basemap. Ceres map tiles: The Ceres atlas will be produced in a scale of 1:750,000 and will consist of 15 tiles that conform to the quadrangle schema for small planets and medium size Icy satellites. A map scale of 1:750,000 guarantees a mapping at the highest availa-ble Dawn resolution in HAMO. Nomenclature: The Dawn team proposed to the International Astronomical Union (IAU) to use the names of gods and goddesses of agriculture and vege-tation from world mythology as names for the craters. This proposal was accepted by the IAU and the team proposed names for geological features to the IAU based on the HAMO mosaic. These feature names will be applied to the map tiles.