J/A+A/614/A15 Mars Express astrometric obs. of Martian moons (Ziese+, 2018)
Mutual event observations of Solar system objects by SRC on Mars Express.
Analysis and release of observations.
Ziese R., Willner K.
<Astron. Astrophys. 614, A15 (2018)>
=2018A&A...614A..15Z 2018A&A...614A..15Z (SIMBAD/NED BibCode)
ADC_Keywords: Positional data ; Minor planets ; Planets ; Solar system
Keywords: astrometry - ephemerides -
planets and satellites: individual: Phobos -
planets and satellites: individual: Deimos
Abstract:
Both Martian moons, Phobos and Deimos, have been observed during
several imaging campaigns by the SRC on Mars Express. Several tens of
images are obtained during mutual event observations - when the
Martian moons are both observed or together with another solar system
body. These observations provide new opportunities to determine the
bodies' positions in their orbits. A method was sought to automate the
observation of the positions of the imaged bodies. Within one image
sequence a similarly accurate localization of the objects in all
images should be possible. Shape models of Phobos and Deimos are
applied to simulate the appearance of the bodies in the images.
Matching the illuminated simulation against the observation provides a
reliable determination of the bodies' location within the image. To
enhance the matching confidence several corrections need to be applied
to the simulation to closely reconstruct the observation. In total 884
relative positions between the different objects are provided.
Description:
Astrometric measurements were obtained from frame images of the SRC on
Mars Express.
The images were obtained during mutual event observations - when the
Martian moons are both observed or together with another solar system
body. Thus, the absolute camera pointing is irrelevant.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
phodei.dat 98 261 Astrometric observations of Phobos w.r.t. Deimos
and to MEX spacecraft position
deisat.dat 160 182 Astrometric observations of Deimos w.r.t. Saturn
and to MEX spacecraft position
phojup.dat 160 151 Astrometric observations of Phobos w.r.t. Jupiter
and to MEX spacecraft position
phosat.dat 160 295 Astrometric observations of Phobos w.r.t. Saturn
and to MEX spacecraft position
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See also:
J/A+A/488/361 : Mars Express astrometric obs. of Phobos (Willner+, 2008)
J/A+A/545/A144 : Astrometric observations of Deimos (Pasewaldt+, 2012)
J/A+A/572/A104 : Astrometric obs. of Phobos and Deimos in 1971 (Robert+, 2014)
J/A+A/580/A28 : Astrometric observations of Phobos (Pasewaldt+, 2015)
J/A+A/603/A55 : WISE/NEOWISE Mars-crossing asteroids (Ali-Lagoa+, 2017)
Byte-by-byte Description of file: phodei.dat deisat.dat phojup.dat phosat.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Image Image name
21- 30 A10 "YYYY-MM-DD" Obs.Date Date of image acquisition/observation
33- 44 A12 "h:m:s" Obs.Time Time of image acquisition/observation
47- 55 F9.2 km Xpos X coordinate of MEX spacecraft in
Mars-centered ICRF frame
58- 66 F9.2 km Ypos Y coordinate of MEX spacecraft in
Mars-centered ICRF frame
69- 77 F9.2 km Zpos Z coordinate of MEX spacecraft in
Mars-centered ICRF frame
80 A1 --- Bound Phobos at boundary (B) or not (N)
83- 89 F7.5 deg AngSep Angular separation
92- 98 F7.5 deg e_AngSep 3-sigma error on AngSep
101-109 F9.5 deg RAdeg ? Right ascension (ICRF) of Phobos or
Deimos w.r.t. spacecraft position (1)
112-118 F7.5 deg e_RAdeg ? 3-sigma error on RAdeg
121-129 F9.5 deg DEdeg ? Declination (ICRF) of Phobos or Deimos
w.r.t. spacecraft position (1)
132-138 F7.5 deg e_DEdeg ? 3-sigma error on DEdeg
141-149 F9.5 deg RA2deg ? Right ascension (ICRF) of Jupiter or
Saturn w.r.t. spacecraft position (1)
152-160 F9.5 deg DE2deg ? Declination (ICRF) of Jupiter or
Saturn w.r.t. spacecraft position (1)
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Note (1): No positions for phodei.dat file.
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Acknowledgements:
Ramona Ziese, ziese(at)tu-berlin.de
(End) Ramona Ziese [TUB, Berlin], Patricia Vannier [CDS] 31-Jan-2018