Description of the PPAS Format

This information was taken directly from the "ppas8.txt" file.

5. PPAS format

Every line (each line is ended by an 'end-of-line' character) contains one
observation. In order to make processing easy, we have used a standard format.
In this format each line is divided in columns and every column always con-
tains the same data. Normally each line contains 80 columns (or characters),
but in order to save space on the disk, every line is ended if the remaining
characters are blank.

This is the format which has been used:

Column       Data
01-08        Cospar-identification of the satellite in the format
             yy-nnncc. yy is the year of launch, nnn is the number
             of the launch (only contains significant numbers and
             is right justified), cc is the piece of the launch (contains
             non-numeric characters). e.g. '86- 39 B' was launched in
             1986 as the 39 th launch and it was a rocket (B). Normally
             an 'A' represents a payload, while everything starting with
             'C','D',... is usually debris. An important exception are the
             Russian C-1 rockets who transport 8 payloads in one into space.
             They always have 'J' as extension.

10-17        Date of observation in the format yy-mm-dd. Here all figures
             are given (even non-significant numbers). e.g. '76-03-01' is
             March 1 in 1976.

19-28        Time of the observation in the format hh:mm:ss.t . All times
             are given in Universal Time (UT). Hours (hh) are measured from 0
             to 23 h. Minutes from 0 to 59 minutes, while seconds can be
             given up to one tenth of a second. Depending on the accuracy
             with which the time was measured, the time can be incomplete.
             A lot of observations merely contain the hour. These are mostly
             observations of the Meeus archive. Attention should be paid to
             observations of which the time is given in this format :
             hh:mm.t. This gives hours, minutes and tenths of a minute. Some
             observers use it to show their accuracy is lower than 1 second.
             This field is blank if no time has been given by the observer.

30-32        An abbreviation of the name of the observer. A list of all abbre-
             viations and the observing place of each observer is given below.
             The abbreviation used, may differ from the initials to avoid
             duplicate identifications.

34-38        Total time in seconds and tenths of a second which passed during
             the measurement of the flash period, in the format sss.t . Only
             recent measurements contain this information. It can be used to
             estimate the effect of a wrong count of periods and to check the
             given period (see below). It is blank if not applicable.

40-42        Accuracy in seconds and tenths of a second on the total time if
             the total time is given. If the total time field is blank, the
             accuracy relates to the period. Some inputs contain '.nn'. This
             means the accuracy (probably on the period) is 0.nn seconds.

44-46        The number of periods counted. The total time divided by the
             number of periods gives the flash period.

48-53        Flash period in seconds and tenths, hundredths (or even thou-
             sandths) of a second in the format ss.tht . The 'point' is
             always found at position 50 unless the period is larger than
             99.999 seconds. The number of figures given is related to the
             estimated accuracy. Usually larger periods have smaller accu-
             racy (i.e. they are less accurate!). This field is blank if no
             period has been measured or if (more likely) the object did
             not show any variation in brightness. In this last case, the
             object is 'STEADY'.

55-80        Remarks on the flash-pattern or on other aspects of the passage.
             A list of abbreviations which are commonly used is given below.
             Normally all remarks are in lowercase, except for 'S' (steady,
             which always comes on position 55 if applicable) and some other.
             All remarks on one observation are divided by commas. Some
             remarks contain numbers in the format 'n)', e.g. '1)'. This is a
             reference to the PPAS.REM-file, which has also been put on the
             disk.
             This file contains remarks which were too long to be put in
             the usual place. Using the name of the satellite and the number
             of the reference it is possible to link both files in mind.


6. Abbreviations in the PPAS-remarks.

The various remarks are separated by a comma and a space. E.g. S, mag +4.

The format for describing the satellites' magnitude is:

mag maximum_magnitude-> minimum_magnitude.

The '+' is omitted for the minimum_magnitude. E.g. mag +4->8  .

When the minimum is invisible, this is indicated with 'inv', e.g.
mag +5->inv. Some observers only mention the maximum_magnitude,
e.g. mag +5.

The following abbreviations are used in the PPAS-remarks-column.


    ?       the photometric period is uncertain, or the remark which
            accompanies this question mark is uncertain.

    a       the photometric period is an approximation.

    amp     amplitude

    b       the observation has been made with binoculars.  This applies
            to most measurements, but is sometimes mentioned explicitly.

    dec     decreasing in brightness. (sometimes mentioned with sm)

    df      two flashes in one period.

    dif     different (maxima)

    dm      double maxima: two close maxima in one period.

    dp      double period: the period measured, has been taken between
            three (instead of two) similar points in the light curve.

    dtm     the period was difficult to measure.

    fm      flat maxima: the brightness remained fairly steady during a
            relatively long time.  Because of this the exact moment of
            maximum is difficult to define.

    hp      half period: the period measured was half of the real period.

    I, irr  irregular brightness pattern, irregularly varying.

    inc     increasing.

    lp      long period.

    min     the period has been measured on the minima in brightness.

    N?      the counted number of maxima is uncertain.

    occ     occasionally.

    ph      photographic observation.

    pm      primary maxima.

    qm      quadruple maxima: four maxima in one period.

    R       regularly varying

    S       the brightness did not (or only very slightly) change,
            except for the variation caused by the change of phase-angle.

    sa      small amplitude : there is a small difference in brightness between
            a maximum and a minimum.

    sec     secondary.

    sf      short flashes, possibly used as maxima.

    sm      a relative (secondary) maximum occured between two absolute
            maxima.

    ssm     some secondary maxima were visible.

    tm      triple maxima: three maxima in one period.

    u       an observation made with the unaided eye.

    var     varying (usually used in the phrase 'slowly var').

    V       varying

    vm      the observed maxima varied in brightness during the observation.

It is possible that even other abbreviations were used. If you would notice
an abbreviation which is not in this list, please report this.

To describe the peculiarities of the flash-pattern (without drawing figures),
the following symbols are put into groups depending on the pattern observed:

    A       smooth primary (or absolute) maximum.

    a       like 'A' but secundary or relative.

    F       sharp (like a flash) primary (or absolute) maximum.

    f       like 'F' but secundary or relative.

    M       flat primary (or absolute) maximum.

    m       like 'M' but secundary or relative.

    _ or -  indicates a minimum or the absence of a (expected) maximum.

    '       the apostrophe usually indicates the maximum on which was counted.
            Sometimes used with _ or - to indicate that the minima were
            counted.

    ,       the comma indicates the location of the minimum which was used to
            count the periods.

Some examples are given below:

     A'A'     a regularly varying object with primary maxima only.

     A'aA'    a regularly varying object with secundary maxima. Primary maxima
              were used to count.

     A'FA_A'  this pattern occurs very frequently in case of Soviet A2-
              rockets. A maximum is followed by a flash (comparable in
              brightness), by another maximum, after which the next flash is
              absent. After this, the pattern is repeated.

     A'fA_A'  the same as the previous one, but the flash is less bright.

     a'Fa_a'  in this case the flash is definetely brighter than the smooth
              maxima.

     M,M      a pattern with two flat maxima divided by a sharply defined
              minimum (which was used to count the periods).

     F'F'     a pattern which has flashes only.