J/other/SoSyR/52.312 Galilean moons positions (Narizhnaya+, 2018)
Astrometric Observations of the Galilean Moons of Jupiter at the
Pulkovo Normal Astrograph in 2016-2017.
Narizhnaya N.V., Khovrichev M.Yu., Apetyan A.A., Bikulova D.A.,
Ershova A.P., Balyaev I.A., Kulikova A.M., Os'kina K.I., Maksimova L.A.
<Solar System Res., 52, 312 (2018)>
=2018SoSyR..52..312N 2018SoSyR..52..312N (SIMBAD/NED BibCode)
ADC_Keywords: Solar system ; Planets ; Positional data
Keywords: Galilean moons of Jupiter - astrometry - CCD observations -
exact positions - theory of satellite motion - theory of planets
Abstract:
Results of the Galilean moons observationals taken with Normal
Astrograph of the Pulkovo Observatory in 2016-2017 are presented. 761
positions of the Galilean moons of Jupiter in the system of the Gaia
DR1 catalog (ICRF, J2000.0) and 854 differential coordinates of the
satellites relative to each other were obtained. The mean errors in
the satellites' normal places and the corresponding root-mean-square
deviations are (eps)RA=0.0020", (eps)DE=0.0027", (sigm)RA=0.0546",
and (sigm)DE=0.0757". The equatorial coordinates of the moons are
compared to the motion theories of planets and satellites. On average,
the (O-C) residuals in the both coordinates relative to the motion
theories are less than 0.031". The best agreement with observations is
achieved by a combination of the EPM2015 and V. Lainey-V.2.0|V1.1
motion theories, which yields the average (O-C) residuals of
approximately 0.02". Peculiarities in the behavior of the (O-C)
residuals and error values in Ganymede have been noticed.
Description:
Our observations were carried out with the Normal Astrograph
(D/F=330mm/3467mm) at Pulkovo (code is 084). The CCD camera
(SBIG ST-L-11K 3 CCD Camera with the 35'x25' field of view and the
0.530"/pixel scale) was used as a radiation detector. In total, for
the observational season, we obtained and processed 3340 CCD frames
containing the images of the Galilean moons. The observations were
made with exposures of 10s, which allowed direct measurements of the
equatorial coordinates of these objects in each of the frames. The
number of the Gaia DR1 reference stars (Arenou et al.,
2017A&A...599A..50A 2017A&A...599A..50A) within a frame ranged from 6 to 18. The duration
of observations within one night reached several hours; consequently,
to calculate the normal places of objects, the positions obtained for
the objects were divided into groups by time intervals of 10min.
To make the measurements of a large body offrames automatic, we
developed the JSA software package that allows the WCS parameters (a
set of constants to convert unambiguously from the pixel coordinates
to the equatorial ones and back) to be determined and introduced into
a metadata block for each of the frames. This method of image analysis
was considered in a series of papers by A. Refregier and his coauthors
(Refregier, 2003MNRAS.338...35R 2003MNRAS.338...35R; Refregier and Bacon,
2003MNRAS.338...48R 2003MNRAS.338...48R; Massey and Refregier, 2005MNRAS.363..197M 2005MNRAS.363..197M).
Astrometric reduction algorithm is based on Turner's method with using
Gaia DR1 catalog as reference one. Ephemerides for comparison are
given by web- server "Natural Satellites Ephemeride Server MULTI-SAT"
developed by N.V. Emelyanov
(http://lnfm1.sai.msu.ru/neb/nss/nssephmr.htm). Two catalogue are
presented: 761 normal positions of Galilean satellites, 854
differential mutual coordinates of Galilean satellites.
File Summary:
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FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
satsdat.dat 72 761 Positions of Galilean satellites
(1-Io, 2- Europa, 3-Ganymede, 4-Callisto)
satsatd.dat 63 854 Differential mutual coordinates of Galilean
satellites
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See also:
J/other/SoSyR/50.344 : Galilean moons + Jupiter positions (Narizhnaya, 2016)
Byte-by-byte Description of file: satsdat.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
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1 I1 --- SatNo [1/4] Identification number of galilean
satellite (1)
3- 18 A16 "date" Obs.Date Mean observation date (YYYY/MM/DD.ddddd)
20- 21 I2 h RAh Right ascension (J2000.0) (2)
23- 24 I2 min RAm Right ascension (J2000.0) (2)
26- 31 F6.3 s RAs Right ascension (J2000.0) (2)
33 A1 --- DE- Declination sign (J2000.0) (2)
34- 35 I2 deg DEd Declination (J2000.0) (2)
37- 38 I2 arcmin DEm Declination (J2000.0) (2)
40- 44 F5.2 arcsec DEs Declination (J2000.0) (2)
46- 52 F7.4 arcsec (O-C)RA (O-C) residual in right ascension (3)
54- 60 F7.4 arcsec (O-C)DE (O-C) residual in declination (3)
62- 66 F5.3 arcsec e_(O-C)RA Error of mean O-C in right ascension
68- 72 F5.3 arcsec e_(O-C)DE Error of mean O-C in declination
--------------------------------------------------------------------------------
Note (1): Satellite number as follows:
1 = Io
2 = Europa
3 = Ganymede
4 = Callisto
Note (2): topocentric equatorial coordinates of Galilean satellites, J2000.0.
Note (3): "Observed-Calculated" residuals by web-sever "MULTI-SAT", calculated
from ephemerides within the EPM2015 and V.Lainey-V.2.0|V1.1 theories.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: satsatd.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 2 I2 --- Sats Idenficiation numbers of galilean
satellites (1)
4- 19 A16 "date" Obs.Date Mean observation date (YYYY/MM/DD.ddddd)
21- 28 F8.3 arcsec dRAs Differential Right ascension (J2000.0) (2)
30- 37 F8.3 arcsec dDEs Differential Declination (J2000.0) (2)
39- 44 F6.3 arcsec (O-C)RA (O-C) residual in right ascension (3)
46- 51 F6.3 arcsec (O-C)DE (O-C) residual in declination (3)
53- 57 F5.3 arcsec e_(O-C)RA Error of mean O-C in right ascension
59- 63 F5.3 arcsec e_(O-C)DE Error of mean O-C in declination
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Note (1): Identification numbers of satellites which observations were used for
deriving differential mutual satellites coordinates relative to each other.
Note (2): Differential coordinates of Galilean satellites (J2000.0) relative
each other.
Note (3): "Observed-Calculated" residuals by web-sever "MULTI-SAT", calculated
from ephemerides within the EPM2015 and V.Lainey-V.2.0|V1.1 theories
--------------------------------------------------------------------------------
Acknowledgements:
Natalia Narizhnaya, Narizhnaya.nat(at)yandex.ru
(End) Natalia Narizhnaya [GAO, Russia], Patricia Vannier [CDS] 02-Aug-2018