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 05 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: 00000000011111111112 12345678901234567890 Example: SSSS YYMM T.tSF PPPE 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 9012345678901 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: 0000000001111111111222222222233333333334444444444 1234567890123456789012345678901234567890123456789 Example: YYLLLPP HHMMSS.ss HHMMSS+DDMMSSbbbbffff S O 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.