J/A+A/425/1107 Observations of Triton and Proteus (Vieira Martins+, 2004)
Systematic astrometric observations of Proteus.
Vieira Martins R., Veiga C. H., Bourget P., Andrei A. H., Descamps P.
<Astron. Astrophys. 425, 1107 (2004)>
=2004A&A...425.1107V 2004A&A...425.1107V
ADC_Keywords: Planets ; Positional data
Keywords: astrometry - planets and satellites: individual: Proteus
Abstract:
Earth based observations of Proteus are made highly difficult by the
magnitude difference with Neptune, and the closeness to the planet. To
overcome these difficulties, observation campaigns using a Hg-mask
coronograph developed for astrometry are being pursued at the
Laboratorio Nacional de Astrofisica, Brazil. The observations are made
at visible light wavelengths with the 1.6 m reflector telescope. The
large 4'x4' field of view of the camera makes it possible to image a
sufficient number of background stars that are used to carry out the
astrometric analysis of these data.
The first results of the campaigns are presented in this paper. They
include 45 independent observations made over 2 nights in 2002. The
positions are referred to the Hipparcos/Tycho2 (I/239/I/259)frame.
The mean offsets relative to the JPL ephemeris are =0.083"
(σ=0.148") in the x={DELTA}RAcosDE direction, and -0.051"
(σ=0.115") in the y={DELTA}DE direction. Additional astrometric
data need to be collected in order to investigate further the possible
offset of Proteus with respect to the Voyager ephemerides.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 70 66 Topocentric observed positions of Triton and Proteus
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See also:
J/A+AS/120/107 : 1989-1994 CCD observations of Triton (Veiga+ 1996)
J/A+AS/131/291 : 1995-1997 CCD positions of Triton (Veiga+ 1998)
J/AJ/119/936 : 2000-2009 Triton stel. occultation candidates (McDonald+ 2000)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 15 F15.7 d JD Julian Date and fractions of Observation
18- 19 I2 h RAth Triton Right Ascention (J2000)
21- 22 I2 min RAtm Triton Right Ascention (J2000)
24- 29 F6.3 s RAts Triton Right Ascention (J2000)
31 A1 --- DEt- Triton Declination sign (J2000)
32- 33 I2 deg DEtd Triton Declination (J2000)
35- 36 I2 arcmin DEtm Triton Declination (J2000)
38- 42 F5.2 arcsec DEts Triton Declination (J2000)
45- 46 I2 h RAph Proteus Right Ascention (J2000)
48- 49 I2 m RApm Proteus Right Ascention (J2000)
51- 56 F6.3 s RAps Proteus Right Ascention (J2000)
58 A1 --- DEp- Proteus Declination sign
59- 60 I2 deg DEpd Proteus Declination (J2000)
62- 63 I2 arcmin DEpm Proteus Declination (J2000)
65- 69 F5.2 arcsec DEps Proteus Declination (J2000)
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Acknowledgements: Roberto Vieira Martins
(End) Patricia Vannier [CDS] 07-Jul-2004