planet: 6 - Saturn
  satellites: S12-Helene:22
total number: 22
        type: relative
       dates: 1985-1987
 observatory: 874 - Itajuba (Laboratorio Nacional de Astrofisica)

   Veiga C.H., Vieira Martins R. (2000)
   Astrometric photographic observations of Helene.
   Astron. Astrophys. Suppl. Ser. V. 143. P. 405.

         relative to: S6-Titan: 22
     reference frame: astrometric
     centre of frame: topocentre
    epoch of equinox: J2000
          time scale: TT
           reduction: no information
         coordinates: X, Y
    diff. refraction: no information
            receptor: photographic
           telescope: no information
           observers: Veiga C.H., Vieira Martins R.
 data included in standard data file: no

            Astrometric photographic positions of the Saturnian
            satellite Helene obtained from 22 plates taken in 6
            nights are presented. The observations are distributed
            between 5 missions in 1985 and 1987. All positions are
            compared with those calculated by Jacobson (1999,
            personal communication). The residuals have mean and
            standard deviation smaller than 0.25" and 0.30"
          evaluation: The differences  O-C(X), O-C(Y) are published
                      in the article. For these values one have:
                                                     X        Y
                      M. (mean)                    0.178"   -0.101"
                      R.M.S. (root mean square)    0.434"    0.250"
                      The differences  O-C(X)e, O-C(Y)e were also
                      calculated by N.Emelianov with the theory by
                      P. Oberty for Helene and with the theory by
                      Harper & Taylor for Titan.
                      With these O-C one have
                                                     X        Y
                      M. (mean)                   -0.087"   -0.181"
                      R.M.S. (root mean square)    0.470"    0.536"

 Bytes Format Units   Label     Explanations
 1-  4  I4    yr      Obs.Y     Year of the mean instant
                                of observation
     6  I1    ---     Obs.M     Month of the mean instant
                                of observation
 8- 15  F8.5  d       Obs.D     Decimal day of the mean instant
                                of observation
17- 24  F8.3  arcsec  X         Differential topocentric
                                coordinate, {Delta}RAcosDE (1)
26- 32  F7.3  arcsec  Y         Differential topocentric
                                coordinate, {Delta}DE (1)
34- 39  F6.3  arcsec  (O-C)X    Observed minus calculated
                                value of X
41- 46  F6.3  arcsec  (O-C)Y    Observed minus calculated
                                value of Y
Note (1): Differential topocentric coordinates are referred to
          Titan.  The reference system is defined by the mean
          equator and equinox J2000
Obs.Y  Obs.D       X       Y     (O-C)X (O-C)Y
    Obs.M        arcsec  arcsec  arcsec arcsec