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| Titel |
High resolution VESTA LAMO atlas derived from Dawn FC images. |
| VerfasserIn |
Thomas Roatsch, Elke Kersten, Klaus-Dieter Matz, Frank Preusker, Frank Scholten, Ralf Jaumann  , Carol A. Raymond, Cris T. Russell |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250072595
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| Zusammenfassung |
| Introduction: NASA’s Dawn spacecraft entered orbit of the inner main belt asteroid 4 Vesta
on July 16, 2011, and spent about one year in orbit to characterize the geology, elemental and
mineralogical composition, topography, shape, and internal structure of Vesta before it
departed to asteroid 1 Ceres in late 2012. One of the major goals of the mission was a global
mapping of Vesta.
Data: The DAWN mission was mapping Vesta from three different orbit heights during
Survey orbit (3100 km altitude), HAMO (High Altitude Mapping Orbit, 700 km altitude), and
LAMO (Low Altitude Mapping Orbit, 210 km altitude) [1]. The Dawn mission is equipped
with a framing camera (FC) [2] which was the prime instrument during the LAMO phase.
DAWN orbited Vesta during LAMO in 21 cycles between December 2011 and end of April
2012. The framing camera took about 10,000 clear filter images with a resolution of about 20
m/pixel during these cycles. The images were taken with different viewing angles and
different illumination conditions. We selected about 8,000 images for the global coverage of
Vesta.
Data Processing: The first step of the processing chain is to ortho rectify the images to
the proper scale and map projection type. This process requires detailed high-resolution
information of the local topography of Vesta. The global topgraphy was calculated
during the stereo processing of the HAMO images [3] and was used here. The shape
model was used for the calculation of the ray intersection points while the map
projection itself was done onto a sphere with a mean radius of 255 km. The next
step was the mosaicking of all images to one global mosaic of Vesta, the so called
basemap.
Vesta map tiles: The Vesta atlas was produced in a scale of 1:200,000 and consists of 30
tiles that conform to the quadrangle scheme proposed by Greeley and Batson [4] and is used
for example for mapping Mars in a scale of 1:5,000,000. A map scale of 1:200,000
guarantees a mapping at the highest available DAWN resolution in LAMO and results in an
acceptable printing scale for the hardcopy map of 10 pixel/mm. The individual tiles were
separately mosaicked and reprojected.
Nomenclature: The DAWN team proposed to the International Astronomical Union
(IAU) to use the names of vestal virgins and famous Roman women as names for the craters
and to use names of places and festivals associated with vestal virgins for other feature
names. This proposal was accepted by the IAU and the team could propose 50 names
for geological features to the IAU which were also approved [5]. These feature
names were applied to the map tiles. The entire Vesta atlas consisting of 30 map tiles
will become available to the public through the Planetary Photojournal and the
PDS.
References: [1]Â Russell, C.T. and Raymond, C.A., Space Sci. Review, 163, DOI
10.1007/s11214-011-9836-2; [2]Â Sierks, et al., 2011, Space Sci. Rev., 163, DOI
10.1007/s11214-011-9745-4; [3] Preusker, F. et al., this session; [4] Greeley, R.
and Batson, G., 1990, Planetary Mapping, Cambridge University Press; [5]
http://planetarynames.wr.usgs.gov/Page/VESTA/target |
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