R.D.E. Observation Format Description

Positional observations of satellites provide the basis to determine their orbits, and to study their optical characteristics. The latter provide the basis for the accurate brightness predictions that we have come to expect from our favourite prediction software or service.

Positional observations are analysed using computer programs, so observers need a systematic and accurate reporting format, ideally one that can be read by both humans and machines. The R.D.E. format is one of several that meet this need.

This format is named after its main user, Russell D. Eberst. It is an abbreviated and modified form of the U.K. format, in which each report consists of at least three lines.

For example:

2420 0405 0.211 1204
0401203 205744.76 185544+324606 4.0 5.8 3 R

Line 1: contains information common to all of the observations that follow.
        It appears once per report.

Column number:

2420 0405 0.211 1204

Cols  01-04: Observing Site Number.

Cols  06-09: UTC Year and Month of Observation, in YYMM format

Cols  11-13: Time Accuracy, in seconds. Format is T.t

Col      14: Time Standard Code.

             Code 1: radio time signal, e.g. MSF. DIZ, WWV
                  2: U.K. Post Office Speaking Clock
                  3: B.B.C. time pips

Col      15: Position Format Code.

             Russell always uses Code 1, with whole arc seconds:

                       Column 1222222222233
             Code 1: RA/DEC = HHMMSS+DDMMSS

Cols  17-19: Position Accuracy.

             Russell reports 120 arc seconds, as SSS

Col      20: Epoch of star chart used to determine position

             Code 1: 1855
                  2: 1875
                  3: 1900
                  4: 1950
                  5: 2000
                  6: 2050
                  0: any other date, which should be sent separately

                  Russell always uses code 4.

Line 2: contains the day of the month, in a two digit format, including leading zero,
        It always appears on line 2 of a report, and whenever the day of the month of
        the observations changes within a report.

Line 3 - contains the details specific to each observation.
         There is one such line per observation.

Column number:

0401203 205744.76 185544+324606 4.0 5.8 3 R

Cols  01-07: Object's International Designation.

             Cols 01-02: year of launch
             Cols 03-05: sequential number of the launch in the year.
             Cols 06-07: piece from the launch, e.g. piece A denoted as 01

             If object is unknown, enter 9900000.

Cols  09-17: UTC Time of Observation, in HHMMSS.ss format.

Cols  19-24: Observed Right Ascension or Azimuth, in HHMMSS format.

Cols  25-31: Observed Declination or Elevation, in DDMMSS format.

Cols  32-35: Brightest Visual Magnitude

             This is the brightest stellar magnitude attained by the satellite during
             the period of one minute centred on the time of the observation, It is
             entered as a 3 digit number.

             If magnitude is negative, enter "-" in column 32
             Columns 32-35 state the numerical value, formatted as M.m

Cols  36-39: Faintest Visual Magnitude

             Format is the same as for Brightest Visual Magnitude.

             If the magnitude is constant, repeat the Brightest Visual Magnitude entry

Cols  40-42: Flash Period

             Time in seconds between successive maxima, formatted as SSS.sss

             If value is less than 1, show one leading zero.
             Show only significant trailing zeros.
             Omit decimal point for whole number values.

Col      43: Remarks.

             May occur later than col 43, depending upon length of Flash Period entry.

             Code S: steady magnitude
                  I: irregular brightness variations
                  R: regular brightness variations
                  F: flashing with constant flash period
                  X: flashing with irregular flash period
                  E: unusually faint because of eclipse exit/entrance

Links to: The VSO Home Page, Positional Measurements, Position Formats.

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