Contents.
planet: 6 - Saturn
satellites: S9-Phoebe : 7 (1995-1995 : 6, 1997-1997 : 1 )
total number: 7
type: absolute
dates: 1995-1997
observatory: 950 - La Palma
Reference.
Observations communicated to NSDC by :
Derek Jones
Institute of Astronomy Madingley Road,
Cambridge CB3 0HA
United Kingdom
Work: +44 (0)1223 766661
Fax: +44 (0)1223 337523
Home: +44 (0)1954 210314
email: dhpj@ast.cam.ac.uk
Informations.
relative to: absolute
reference frame: astrometric
centre of frame: topocentre
epoch of equinox: J2000
time scale: UTC
reduction: DSS-II, USNO ACT
coordinates: absolute
diff. refraction: no information
receptor: CCD
telescope: Jacobus Kapteyn Telescope, D = 1 m.
observers: Harper D., Beurle K.
data included in standard data file: no
Comments.
The pixels were 0.33 arcsec and the CCD chip size 330 arcsec on
the side. A red (R) filter was used and the exposure was 64 sec.
It is straightforward to measure the position of Phoebe and about
ten reference stars on each exposure. The positions of the
reference stars were measured on the Digital Sky Survey (DSS-II
with 1 arcsec pixels) together with about ten stars from the USNO
ACT catalogue, all within 0.7 degrees of the CCD fields. The
goodness of fit was 0.12 arcsec, rms in one co-ordinate.
The goodness of fit of the reference stars to the positions
measured on the CCD was smaller. Phoebe was measured relative to
the same reference stars within each night but relative to a
different set of reference stars on different nights. The
scatter of the residuals relative to the JPL Horizons ephemeris
within nights was much smaller than from night to night. This
indicates that the accuracy is simply the accuracy of the star
positions, i.e. 0.12 arcsec.
The observations have been combined into one normal place for
each of the seven nights with an rms scatter of 0.04 arcsec
within nights.
Format.
1. Julian date in MJD (JD - 2400000.5) UTC
2. Hour of right ascension (alpha, h)
3. Minute of right ascension (alpha, m)
4. Second of right ascension (alpha, s)
5. Degree of declination (delta, deg)
6. Minute of declination (delta, ' )
7. Second of declination (delta, '' )
8. The residuals in right ascension (arcsec) from the JPL Horizons
ephemeris
9. The residuals in declination (arcsec) from the JPL
Horizons ephemeris
10. The number of CCD exposures (n).
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Date in MJD alpha delta residuals(arcsec)
h m s deg ' '' alpha delta n
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