SIMPLE  =                    T                                                  BITPIX  =                    8                                                  NAXIS   =                    2                                                  NAXIS1  =                   60                                                  NAXIS2  =                 3332                                                  OBJECT  = 'P/HALLEY'                                                            FILE-NUM=               077009                                                  DATE-OBS= '14/03/86'                                                            TIME-OBS=               .02084                                                  DATE-REL= '22/04/90'                                                            DISCIPLN= 'GIOTTO/PIA'                                                          LONG-OBS= '999/99/99'                                                           LAT--OBS= '+99/99/99'                                                           SYSTEM  = '05009977'                                                            OBSERVER= 'KISSEL,J/ET AL.'                                                     SUBMITTR= 'KISSEL,J'                                                            SPEC-EVT=                    F                                                  DAT-FORM= 'ASCII   '                                                            COMMENT   ADD. OBS. BROWNLEE,D.E/BUECHLER,K/CLARK,B.C/FECHTIG,H/GRUEN,E         COMMENT   ADD. OBS. HORNUNG,K/IGENBERGS,E.B/JESSBERGER,E.K/KRUEGER,F.R/KUCZERA,HCOMMENT   ADD. OBS. MCDONNELL,J.A/MORFILL,G.M/RAHE,J/SCHWEHM,G.H/SEKANINA,Z     COMMENT   ADD. OBS. UTTERBACK,N.G/VOELK,H.J/ZOOK,H.A                            COMMENT   ORIGINALLY NAMED PIA3M0.DAT AT MPIK, HEIDELBERG                       COMMENT   CONTAINS MODE 0 SPECTRA                                               COMMENT   SEQ       - INDEX OF TRANSMITTED SPECTRA                              COMMENT   TC        - TEST PULSE COUNTER (THIS IS *NOT* A TEST PULSE)           COMMENT   LEN       - LENGTH OF THE SPECTRUM IN THE ORIGINAL ESA-EDF            COMMENT               WITHOUT THE HEADER                                        COMMENT   SEN       - SENSITIVITY / FRONT-END TRIGGER LEVEL H OR L.             COMMENT                THE INSTRUMENT SWITCHES FROM HIGH ("H") SENSITIVITY      COMMENT                TO LOW ("L") SENSITIVITY WHEN THE IMPACT RATE EXCEEDS    COMMENT                A CERTAIN LEVEL. iN THE LOW SENSITIVITY MODE THE 3       COMMENT                THRESHOLD-LEVELS "1", "3", AND "7" ARE A FACTOR OF 100   COMMENT                HIGHER THAN IN THE HIGH SENSITIVITY MODE, SO THAT THE    COMMENT                LEVEL "1" IN THE "L" SENSITIVITY SHOULD CORRESPOND TO    COMMENT                THE LEVEL "7" IN THE "H" MODE FOR AN IDENTICAL           COMMENT                SIGNAL HEIGHT.                                           COMMENT   HV        - MULTIPLIER HIGH VOLTAGE / VALUE IN VOLTS                  COMMENT   TPOS      - TARGET POSITION. THE QUALITY OF THE MASS SPECTRA LARGELY  COMMENT                DEPENDS ON THE CLEANLINESS OF THE TARGET.MOVEMENT OF THE COMMENT                TARGET IS EFFECTED IN TWO WAYS: BY TELECOMMAND AND       COMMENT                AUTOMATICALLY. A TELECOMMAND WILL BE USED PRIOR TO       COMMENT                ENCOUNTER TO REMOVE THE TARGET AREA THAT HAS BEEN        COMMENT                EXPOSED TO THE ENVIRONMENT DURING TESTS AND LAUNCH.      COMMENT                DURING THE ACTUAL FLYBY, THE TARGET STARTED MOVING       COMMENT                WHENEVER IR4 > 60 AND STOPPED WHEN IR < 30.              COMMENT   SPOS      - SHUTTER POSITION. SHUTTER STATUS:                         COMMENT                 0: THE SHUTTER IS FULLY OPEN (479 MM**2)                COMMENT                10: THE SHUTTER IS 83% OPEN (390 MM**2)                  COMMENT                20: THE SHUTTER IS 64% OPEN (302 MM**2)                  COMMENT                30: THE SHUTTER IS 45% OPEN (213 MM**2)                  COMMENT                40: THE SHUTTER IS 28% OPEN (132 MM**2)                  COMMENT                50: THE SHUTTER IS 15% OPEN ( 69 MM**2)                  COMMENT   FIS       - FILE SECTION / AREA OF PIA'S MEMORY                       COMMENT   CCE       - CLASS OF CURRENT EVENT:                                   COMMENT                CLASS-1: EVENTS THAT HAVE ONE FRONT-END SIGNAL ONLY.     COMMENT                CLASS-2: EVENTS THAT HAVE ONE COINCIDENCE BETWEEN TWO    COMMENT                 FRONT-END CHANNELS, BUT NO SPECTRUM.                    COMMENT                CLASS-3: EVENTS THAT HAVE ALL FRONT-END COINCIDENCES,    COMMENT                 BUT NO SPECTRUM.                                        COMMENT                CLASS-4: EVENTS THAT HAVE A MINIMUM OF 52/46/10 ENTRIES  COMMENT                 IN THE SPECTRUM FOR MODES 1/2/3, RESPECTIVELY.          COMMENT                CLASS-5: EVENTS THAT HAVE A MINIMUM OF 54/48/12, BUT NOT COMMENT                 MORE THAN 228/148/140 ENTRIES IN THE SPECTRUM, AND IN   COMMENT                 ADDITION A MINIMUM OF 26/21/6 ENTRIES IN THE MASS       COMMENT                 WINDOW (6 - 58 U).                                      COMMENT                CLASS-6: CLASS-5 EVENTS THAT HAVE, IN ADDITION, A        COMMENT                 MINIMUM OF 2 ENTRIES OF AT LEAST 1/5TH FULL SCALE       COMMENT                 BETWEEN MASS 5 AND 8.                                   COMMENT                CLASS-7: CLASS-5 EVENTS THAT HAVE A MINIMUM OF 34/27/12  COMMENT                 ENTRIES IN THE MASS WINDOW, BUT NO MORE THAN 93/49/46.  COMMENT                CLASS-8: EVENTS OF THE STATISTICAL SAMPLE.               COMMENT                CLASS-9: TEST PULSES FROM THE TEST-PULSE SEQUENCE.       COMMENT                CLASS-0: EVENTS THAT HAVE ALREADY BEEN TRANSFERRED       COMMENT                 TO TELEMETRY.                                           COMMENT                N O T E: CLASS-9 IS NOT TRIGGERED BY EVENTS.             COMMENT   ENR       - EVENT NUMBER / INDEX OF ALL IMPACT EVENTS                 COMMENT   TIME      - SPACECRAFT-TIME / RELATIVE TIME; 1=0.11852 SEC            COMMENT                EXACTLY: 1 = 1/(138240 HZ / 2**14) = 0.11852 SEC         COMMENT   SEC       - SPACECRAFT-SECTOR. SOLAR ASPECT, OR ANGULAR POSITION OF   COMMENT                THE PIA INSTRUMENT, RESPECTIVE TO THE SUN. THE           COMMENT                360 DEGREES ARE DIVIDED INTO 256 SECTORS.                COMMENT   TEL       - TELEMETRY MODE + SPECTRUM MODE                            COMMENT               SPECTRUM MODE:                                            COMMENT                MODE 0: 15 MHZ MODE. AN AMPLITUDE SAMPLE OF THE MP       COMMENT                        OUTPUT IS TAKEN EVERY 66.66 NS AND STORED IN     COMMENT                        THE EVENT MEMORY                                 COMMENT                MODE 1: MAX/MIN MODE. FOR EACH MAXIMUM APPEARING AT      COMMENT                        THE MP-OUTPUT, AN AMPLITUDE SAMPLE AND A SAMPLE  COMMENT                        OF THE T**2-GENERATOR IS TAKEN. A SECOND SET OF  COMMENT                        SAMPLES IS TAKEN HALF A MASS LATER (MINIMUM      COMMENT                        SAMPLE). IN ADDITION, AN AMPLITUDE SAMPLE IS     COMMENT                        TAKEN EVERY 1.13 MUSEC, IF NO OTHER MAXIMUM      COMMENT                        SAMPLE OCCURED.                                  COMMENT                MODE 2: MAX/TIME MODE. FOR EACH MAXIMUM IN THE SPECTRUM, COMMENT                        AN AMPLITUDE/T**2 ENTRY INTO THE MEMORY OCCURS.  COMMENT                        ADDITIONALLY, AN AMPLITUDE SAMPLE IS TAKEN EVERY COMMENT                        1.13 MUSEC IF NO OTHER SAMPLING OCCURED.         COMMENT                MODE 3: MAX MODE. SAME AS MODE 2, BUT TIME SAMPLES TAKEN COMMENT                        ONLY AFTER 8.6 MUSEC.                            COMMENT   PM        - AMPLITUDE PHOTOMULTIPLIER   / FRONT-END CHANNEL           COMMENT   TG        - AMPLITUDE TARGET            / AMPLITUDES (1 IS LOWEST,    COMMENT   AC        - AMPLITUDE ACCELERATION GRID / 3 IS FACTOR OF 10 HIGHER    COMMENT   MON       - AMPLITUDE MONITOR           / THAN 1, 7 IS FACTOR OF      COMMENT   CA        - AMPLITUDE CATCHER           / 10 HIGHER THAN 3;           COMMENT                                           / SENSITIVITY TOGGLES X100)   COMMENT   KOIN      - COINCIDENCES REQUESTED / MIN FRONT-END CHANNELS TO TRIG   COMMENT             - COINCIDENCES ACTUAL / CHANNELS TRIGGERED THIS EVENT       COMMENT   IR        - THE ACTUAL 'IMPACT RATE', I.E. THE NUMBER OF EVENTS       COMMENT               OCCURING PER SECOND                                       COMMENT   IR4       - NUMBER OF EVENTS PER SECOND THAT ALSO SHOW A SPECTRUM     COMMENT               CORRESPONDING TO A CLASS-4 TO -7 EVENT.                   COMMENT   IRL       - NUMBER OF EVENTS PER SECOND, LARGER THAN ITS              COMMENT               X100 THRESHOLD                                            COMMENT   CLI1-5    - CLASS COUNTER / CLASS 1 IS SINGLE FRONT-END CHANNEL       COMMENT               TRIGGER; CLASS 7 IS ALL TRIGGERS COINCIDENT AND MANY      COMMENT               LINES IN SPECTRUM; SEE REFERENCE FOR DETAILS              COMMENT   NA        - NUMBER OF NON-ZERO AMPLITUDES / WITH FLAG=0               COMMENT   N0        - NUMBER OF ZERO AMPLITUDES / WITH FLAG=0                   COMMENT   MA        - MAXIMUM PEAK OF THE SPECTRUM                              REFERNC = 'KISSEL, J., ESA SPECIAL PUBLICATION 1077, MARCH, 1986, 67-83'        REFERNC = ' ARTICLE TITLE: THE GIOTTO PARTICULATE IMPACT ANALYZER'              REFERNC = '  VOLUME TITLE: THE GIOTTO MISSION - ITS SCIENTIFIC INVESTIGATIONS'  REFERNC = ' VOLUME EDITORS: REINHARD, R. AND BATTRICK, B.'                      COMMENT   DURING ACTUAL HALLEY FLYBY TWO OUT OF SIX MULTIPLIER-AMPLIFIERS       COMMENT   FAILED, YIELDING INCORRECT AMPLITUDE INFORMATION IN THE MASS          COMMENT   SPECTRA CHANNEL; TO OBTAIN PARTIAL CORRECTION FOR AMPLITUDE,          COMMENT   USE F(A) WHERE F(0)=0, F(1...4)=A*2+21, F(5...8)=A+25,                COMMENT   F(9...14)=A+26, F(15...16)=A+27, F(17-19)=A+2B, F(20)=49,             COMMENT   F(21)=52, F(22)=57, F(23...25)=3*(A-23)+62, F(26...83)=A+44,          COMMENT   F(84...127)=128.                                                      COMMENT   NOTE: DESPITE THIS CORRECTION THE AMPLITUDE RANGES 1...22 AND         COMMENT   AROUND 51...65 ARE INCOMPLETE.                                        END