Photometric Periods of Artificial Satellites -------------------------------------------- 1. Introduction This database of Photometric Periods of Artificial Satellites (PPAS) has been collected by the Belgian Working Group of Satellites (BWGS). It can be used for research on flash periods of artificial satellites. So far research on this subject has been hampered by the lack of obser- vational data. We hope this database can leviate that problem. The idea to create this database came from Christian Steyaert who dis- covered the old archive of Jean Meeus (with observations from 1962 until 1978) in 1988. While working on the informatisation of the (new) obser- vations of the BWGS (which restarted its activities in 1987), the idea grew to collect all old observations as well. Apart from Jean Meeus' archive another major source was found in Bertus Kroon's archive. The observations of the Dutch group that formed around him limited the gap between Jean Meeus' archive (until 1978) and the current activities of the BWGS (from 1987 onwards new observations guarantee a follow-up). 2. Versions PPAS 1 was published in October 1990. PPAS 2 appeared at the end of 1991. Added were new observations ob- tained between August 1990 and September 91, and some older observations (obtained from the archives of our active observers). PPAS 3 appeared at the end of 1992. The archive of Pierre Neirinck and Daniel Karcher was added, as were all new observations between September 91 and August 92. PPAS 4 was published early 1994. New observations between August 1992 and November 1993 were included. Some small errors were also corrected. PPAS 5 appeared in January 1995. Part of the archive of the late Horst Koehnke was added, as were all observations obtained between December 1993 and December 1994. PPAS 6 was published in April 1996. It contains more of the archive of Horst Koehnke, as well as new observations obtained between December 1994 and March 1996. The remarks-file PPAS6.REM was cleaned up and the indexing of the remarks was improved. PPAS 7 appeared in May 1997. It contains another part of the archive of Horst Koehnke, as well as new observations obtained between April 1996 and May 1997. Thanks to the effort of mainly Leo Barhorst a number of faulty entries in our archive were corrected. PPAS 8 appeared in January 1999. It contained a number of observations of Mike McCants' archive, as well as new observations obtained between May 1997 and December 1998. 3. Collaborators Our thanks go to the following people: - Bart De Pontieu, Bram Dorreman, Kurt Jonckheere, Kurt Osaer, Christian Steyaert and Patrick Wils who entered all PPAS 1 observations. - Jean Meeus, Bertus Kroon, Pierre Neirinck and Horst Koehnke for their archives. - Dirk Carlens, Tristan Cools, Bart De Pontieu, Johannes Fritzer, Kurt Jonckheere and Jan Vansteelandt for entering the archives of Pierre Neirinck and Horst Koehnke. - Kurt Jonckheere for collecting our monthly observations until July 1992. - Bart De Pontieu for collecting our monthly observations between July 1992 and May 1993. - Tristan Cools for collecting our monthly observations from May 1993 until April 1996. - Kurt Jonckheere and Leo Barhorst for collecting our monthly observations from April 1996 until August 1996. - Kurt Jonckheere for collecting our monthly observations from August 1996 until December 1998. - all observers for sending in their monthly observations since 1991. Further acknowledgement goes to the following persons : PPAS 1 : Bram Dorreman for first editing, uniformisation and synchronisation between the different sources of PPAS 1. PPAS 2, 3, 4 : Bart De Pontieu and Kurt Jonckheere for uniformisation and final editing of these PPAS versions. PPAS 5 : Tristan Cools for uniformisation and final editing of PPAS 5. PPAS 6 : Tristan Cools for uniformisation and final editing of PPAS 6. PPAS 7 : Kurt Jonckheere for uniformisation and final editing of PPAS 7. PPAS 8 : Kurt Jonckheere for uniformisation and final editing of PPAS 8. Finally we would like to thank all observers, who despite such hazards as cold, frustration, fights with the family and other harsh circumstances persevered and produced such a vast amount of scientific data. 4. Technical details The PPAS consists of 41 Text or ASCII-files (one for each launch year) which contain the observations of the satellites launched in that year. All PPAS- files have the extension '.OBS'. E.g. The file 'PPAS91.OBS' contains all observations of satellites which were launched in 1991. It should be noted that the names of all satellites launched before 1963 have been COSPAR-ized. Official notation uses Greek letters for them. We have chosen to translate all Greek names to the current COSPAR system (to avoid trouble with the Greek characters). e.g. 61- alpha kappa 4 becomes 61- 34 D. USSPACECOM have also adopted this system in 1993. The file 'PPAS8.REM' contains remarks that were too long to be fitted into the 80 column PPAS-format (see below). The remarks are numbered per satellite. The numbers in the remarks column of the PPAS-format (e.g. '1)') refer to the PPAS7.REM file. 5. Special 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. 7. Observers of the PPAS AB A.C. Beresford Adelaide Australia AF Alain Figer Martigues, Paris France ANO Antero Olkkonen Ristiina Finland AP Alphonse Pouplier Wepion Belgium AR Alberto Rango Livorno Italy AS Alexander Seidel Lemgo FRG Stade/Elbe FRG, from 1983 on BB Bjorn Bonny Eernegem Belgium BD Bram Dorreman Achel Belgium BDP Bart De Pontieu Oostende Belgium BG Bill Gates Albuquerque, New Mexico USA BJG Bjoern Gimle Junibacken Sweden BK Bertus Kroon Apeldoorn The Netherlands BP Bengt-John Piolon Oostende Belgium BPW Bruce P. Watson Denver USA BV Boris Vrancken Oostende Belgium BY Brad Young Tulsa, OK USA CE Christopher Engelhardt Fulda FRG CK ? CS Christian Steyaert Geel Belgium CT Cal Tech California USA CW Chris Wyatt Bendigo, Victoria Australia DA A. d'Allessandro Genua Italy DAP David Alan Pickup Edinburgh Scotland DB David M. Brierley Manchester Great-Britain DC Dirk Carlens St.Lambrechts-Herk Belgium DG Doyle J. Groves Noblesville, Indiana USA DH David Hopkins Great-Britain DIB Dietmar Buettner Chemnitz Germany DJL D.J. Lazlo Denver, Colorado USA DK Daniel Karcher Wittenheim France DL Dirk Laurent Mechelen Belgium DM Harry De Meyer Sint-Kruis, Brugge Belgium DMB David M. Brierley Colorado Springs USA DSB Douglas Biggerstaff Toronto Canada DW D. West Austin, Texas USA DWB David W. Bishop Utica, New York USA EC Ed Cannon Austin, Texas USA EL Ed Light Lakewood, NJ USA EN Elisabeth Nuyts Kessel-Lo Belgium ER Eero Rantalaiho Varkkala Finland EV Eric Vondra Wampum, PA USA FD Frank Dempsey Ajax, Ontario Canada FF Franco Foresta Palermo, Sicily Italy FR Frank Reed Scottsdale, Arizona USA FV Fritz Verhelst Ekeren, Antwerpen Belgium FW Frank Weissferdt Selters FRG GAR Greg Retzlaff Saskatchewan Canada GH Gary Holahan Silver Spring, Maryland USA GL Ulrich Gentzel-Lingner Heidelberg FRG GM Gunter Monz Peterberg Germany GR Greg Roberts Kaapstad South-Africa HA ? HB Hermann Boehnhardt Rodental-Moenchreden FRG HD ? HK Horst Koehnke Stade-Elbe FRG HS Hermann Schnitzler Grevenbroick FRG HVB Hendrik Vandenbruane Beernem Belgium IL Inge Leyssens Edegem Belgium IP ? IPO Ian Porter Australia JA Jan Aelbrecht Belgium JC Johan Claes Oostende Belgium JDW Jean De Weerdt Gistel Belgium JDG Don Gardner JEV Jim Varney Sacramento, California USA JG Jason Gibson Melbourne Australia JH Johan Hoste Oostende Belgium JHR Jay H. Respler Freehold, New Jersey USA JL Jean Lecacheux Meudon France JM Jean Meeus Kessel-Lo (till 67-06-30) Belgium Korbeek-Lo Belgium Erps-Kwerps (fr 16-07-68) Belgium JN Jim Nix Memphis, TN USA JO J. Oudman Groningen The Netherlands JOP Joel Piraux Marseille France JP John Prentice Albuquerque, New Mexico USA JPH Jason Hatton Strasbourg France JR J. Ruland Hasselt Belgium JR Juergen Renn Moers FRG JS Jan Strobbe Eernegem Belgium JSC Jim Scotti Tucson, AZ USA JV Jaap Veltekamp Vries The Netherlands Groningen The Netherlands JVB Jan Vandenbruane Beernem Belgium JVS Jan Vansteelandt Leuven Belgium JVW Jeroen Van Wassenhove Nazareth Belgium JW Joel Weisberg Albuquerque, New Mexico USA KAH Kai Hamalainen Lappeenranta Finland KB Ken Boedt Oostende Belgium KD Kurt Dequick Bredene Belgium KDL Kris Delcourte Belgium KH Kevin Hestir Albuquerque, New Mexico USA KJ Kurt Jonckheere Oostende Belgium KO Kurt Osaer Bredene Belgium KVG Karin Van Genegen Mortsel Belgium LA Georges Lauwers Zemst Belgium LB Leo Barhorst Ede + Alkmaar The Netherlands LG Lloyd R. Gibson Thallon, Queensland Australia LL L. Langeville Brussels Belgium LP Lieven Van Parijs Meulebeke Belgium LR Leo Rajala Jamsa Finland LS Lutz Schindler Braunschweig Germany LW Leo Wikholm Helsinki Finland MA D.C. Mason Tremadoc,Caernarven,Wales Great-Britain MAD Madison USA? MAG Mauritz Geyser South-Africa MD Alistair Macdonald Toronsville Australia MF Matthew Francey Mississauga, Ontario Canada MG ? MJ Michel Jacquesson Sevigny-Waleppe France MM Mike McCants Austin, Texas USA MO Marc Moors Bonheiden Belgium MPM ? MR Mike Rosseel Belgium MS Markku Siljama Mantyharju Finland MVP Michel Van de Putte Ronse Belgium MW ? MZ Grupo Espacial Mendoza Argentina NB N.J. Budd UK NC Neil Clifford Oxford UK PA Peter Aneca Bredene Belgium PC Patrick Carpreau Mechelen Belgium PDV Patrick Devreese Moen Belgium PEW Peter Wakelin Ascot, Berkshire UK PIA Pieter Audenaert Gent Belgium PK Petteri Kankaro Merimasku Finland PM Paul Maley Houston, Texas USA PN Pierre Neirinck Malo-Les-Bains France PP Pieter Passchijn Eernegem Belgium PR Paul Roggemans Mechelen Belgium PS Patrick Schmeer Saarbruecken-Bischmisheim Germany PW Patrick Wils Niel Belgium Boortmeerbeek Belgium RD Rudy Dequick Bredene Belgium RE Russell Eberst Edinburgh, Scotland Great-Britain RGL Ron Lee Falcon USA RIK Richard Keen Coal Creek USA RK Rainer Kracht Elmshorn Germany RM Rob Matson Belmont Shore, CA USA RMC Ralph McConahy Barstow, CA USA RO Jean-Pierre Rohart Wormhout France RS Robert Sheaffer San Jose, CA USA RW Ron Welch Watson Australia SA Sacramento California USA SL Stefan Lobet Kontich Belgium ST San Antonio California USA SW Sue Worden USA TC Tristan Cools Brugge Belgium TD Tommy Deslijpere Oostende Belgium TH Terre Haute France TID Tim Daniels Edegem Belgium TK Takeshi Kawabata Yokohoma Japan TM ? TR Tuomo Roine Helsinki Finland TT Tuomas Torronen Espoo Finland VAG Vince Gardiner Australia VB Isi Van den Broeck Londerzeel Belgium Duffel Belgium VC Paul Van Cauteren Aartselaar Belgium VG Vincent Gathot Eernegem Belgium VH Luc Vanhoeck Puurs Belgium VI Van Iseghem Sint-Kruis, Brugge Belgium VL Frans Van Loo Itegem Belgium VM Veikko Makela Helsinki Finland VN Van Nuys Belgium WD Werner Depoorter Halle-Zoersel Belgium WH Wim Holwerda Loon-op-Zand The Netherlands WJW William J. Welker Pittsburgh USA WN Walter Nissen Silver Spring USA WPK Willie Koorts Wellington South Africa WV Willy Verhaegen Wetteren Belgium YY Yoshiro Yamada Yokohama Japan (As of 1999,) In total 166 observers produced 48648 observations. If possible the location of the observations has been given. Some observers have moved or made observations on a vacation trip. There is one double identification i.e. the initials JR are the same for Juergen Renn and J. Rulandt (both made one observation)/ There are a few unidentified observers, whose names have been lost. None have made more than a couple of observations. Half of the observers have made less than 50 observations. Some of those are not very experienced, which might influence the quality of the observations. More than 50 observers are active at this moment. An asterisk '*' is given next to the name of the active observers. All satellite observers are warmly encouraged to join our group. 6. Use of PPAS The PPAS is free of charge. It is updated regularly with new observations. The updates are available from the same archive as where you find this text. For more information contact the address below. If you happen to notice errors, please report them. Also, all users are invited to send their own observations (in the PPAS-format) to us. All information on future versions of PPAS will appear on SeeSat-L and on the www-pages of the Visual Satellite Observers Home Page. It may be interesting to note that the BWGS has developed a software package (SatFlash) which facilitates analysis of the PPAS data. The PPAS-data may be used for scientific analysis, provided the source is mentioned. You can find more information about the Belgian Working Group Satellites on the Visual Satellite Observers Home Page: http://www.satobs.org/tumble/tumbleintro.html http://www.satobs.org/tumble/flashpm.html http://www.satobs.org/tumble/rotandfp.html http://www.satobs.org/tumble/rottheory.html http://www.satobs.org/tumble/expresfpm.html Bram Dorreman Kurt Jonckheere