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File: 1884_henry.data.txt
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     Contents: 
        - 5 observations made from 1884 Jan. 25 to Feb. 12

     References:

         Henry Paul, Henry Prosper, 1884: Observations faites a l'Observatoire de Paris
         Bulletin Astronomique, 1e serie. vol. 1. p. 15, p. 89.


     Format:
  
          . Opposition number (1877 = 1, 1988 = 53)              columns 3-4
          . Observation time (UTC), Not light-time corrected,
		with the form YYYYMMDD.DDDDD                     columns 6-19
          . (ET-UTC) in tenths of second                         columns 21-23
          . Observed body 1 = Phobos relative to Mars
                          2 = Deimos relative to Mars
                          3 = Deimos relative to Phobos          column 32
          . Obs. type     0 = separation and/or position angle
                          1 = differential R.A.(*cosine(dec.))
			      and/or differential declination
                          2 = Delta a or Delta d                 column 34
          . Presence flag for 1st observation of pair
			  0 = observation absent
			  1 = observation present                column 36
          . Presence flag for 2nd observation of pair
			  0 = observation absent
			  1 = observation present                column 37
          . Ref. system,  1 = true equator and equinox of date
			  2 = mean equator and equinox of B1900
			  3 = mean equator and equinox of B1950 
			  4 = mean equator and equinox of J2000  column 39
          . 1st observation of pair (seconds of arc)
			  1 blank if presence flag 0
			  2 see note 4.                          columns 41-48
          . 2nd observation of pair (seconds of arc or degrees if position
            angle)
			  1 blank if presence flag 0
			  2 see notes 1 and 4.                   columns 50-57
          . sigma noise in 1st obs. of pair (seconds of arc)
			    1 blank if presence flag 0
			    2 see notes 3 and 4.                 columns 60-64
          . sigma noise in 2nd obs. of pair (seconds of arc)
			    1 blank if presence flag 0
			    2 see notes 2, 3 and 4.              columns 66-70

Note 1.		The units for the observations are seconds of arc except for 
		position angle where the unit is degrees east of north in the
		range 0 - 360.

Note 2.		The units for the observation noise are always seconds of arc.
		For a position angle p, the noise refers to the product of the
		error in p and the separation angle.		
	
Note 3.		In the ESOC system, when the noise is greater or equal to 99.0
		the corresponding observation is of bad quality and is not used
		in the determination of the orbit but its residual is computed
		and printed.

Note 4.		When the observation is either Delta a or Delta d the columns 
		normally used for the complementary observation are used to
		store the position angle, theta. Also, the columns normally 
		used to store the noise of the complementary observation 
		contain 0.0.



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