Contents.
      planet: 6 - Saturn
  satellites: S12 - Helene: 890
total number: 890
        type: absolute
       dates: 2004-2016
 observatory: Cassini space probe

Reference
   Qingfeng Z., Yutao X., Qingyu P., Xiaohua M., Zhan L., Na W. (2019)
   Astrometric reduction of Cassini ISS images of Helene
   SCIENTIA SINICA Physica, Mechanica & Astronomica, vol. 49, issue 1, p. 019502.
   2019SSPMA__49a9502Q

Informations.
         relative to: absolute
     reference frame: astrometric
     centre of frame: Cassini space probe
    epoch of equinox: ICRF
          time scale: UTC
           reduction: Gaia DR2
         coordinates: absolute
    diff. refraction: no information
            receptor: CCD
           telescope: Cassini ISS narrow angle camera (NAC)
           observers: Cassini space probe
 data included in standard data file: no

Comments.

Format.
   1. Image name
   2. Year of the date of observation
   3. Day in the year of observation
   4. Hour of the date of observation
   5. Minute of the date of observation
   6. Seconds of the date of observation
   7. Right ascension of Helene (RA, degrees)
   8. Declination of Helene (Dec, degrees)
   9. Right ascension of the camera's pointing vector orientation (RAc, degrees)
  10. Declination of the camera's pointing vector orientation (DecC, degrees)
  11. The camera's twist angle (twist, degrees)
  12. Sample coordinate of Helene in the image (sample, pixels)
  13. Line coordinate of Helene in the image (line, pixels)

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Image name  Year Day   Time           RA          Dec       RAc         DecC    twist      sample   line
                     h  m  s        degrees     degrees   degrees     degrees  degrees     pixels  pixels
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