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 87 AF Alain Figer Martigues, Paris France 188 ANO * Antero Olkkonen Ristiina Finland 290 AP * Alphonse Pouplier Wepion Belgium 1 AR * Alberto Rango Livorno Italy 2 AS * Alexander Seidel Lemgo FRG 1292 Stade/Elbe FRG, from 1983 on BB Bjorn Bonny Eernegem Belgium 2 BD * Bram Dorreman Achel Belgium 4126 BDP * Bart De Pontieu Oostende Belgium 1148 BG Bill Gates Albuquerque, New Mexico USA 6 BJG * Bjoern Gimle Junibacken Sweden 20 BK Bertus Kroon Apeldoorn The Netherlands 378 BP Bengt-John Piolon Oostende Belgium 6 BPW Bruce P. Watson Denver USA 2 BV Boris Vrancken Oostende Belgium 1 CE Christopher Engelhardt Fulda FRG 259 CK * ? 2 CS Christian Steyaert Geel Belgium 1 CT Cal Tech California USA 5 CW * Chris Wyatt Bendigo, Victoria Australia 1 DA A. d'Allessandro Genua Italy 3 DAP * David Alan Pickup Edinburgh Scotland 3 DB David M. Brierley Manchester Great-Britain 879 DC Dirk Carlens St.Lambrechts-Herk Belgium 263 DG * Doyle J. Groves Noblesville, Indiana USA 1 DH David Hopkins Great-Britain 23 DIB Dietmar Buettner Chemnitz Germany 148 DJL * D.J. Lazlo Denver, Colorado USA 3 DK * Daniel Karcher Wittenheim France 318 DL Dirk Laurent Mechelen Belgium 8 DM Harry De Meyer Sint-Kruis, Brugge Belgium 3 DMB David M. Brierley Colorado Springs USA 2 DSB Douglas Biggerstaff Toronto Canada 12 DW D. West Austin, Texas USA 23 DWB David W. Bishop Utica, New York USA 35 EC * Ed Cannon Austin, Texas USA 20 EL * Ed Light Lakewood, NJ USA 4 EN Elisabeth Nuyts Kessel-Lo Belgium 12 ER * Eero Rantalaiho Varkkala Finland 71 EV * Eric Vondra Wampum, PA USA 1 FD Frank Dempsey Ajax, Ontario Canada 74 FF Franco Foresta Palermo, Sicily Italy 1 FR * Frank Reed Scottsdale, Arizona USA 2 FV Fritz Verhelst Ekeren, Antwerpen Belgium 33 FW * Frank Weissferdt Selters FRG 189 GAR Greg Retzlaff Saskatchewan Canada 5 GH Gary Holahan Silver Spring, Maryland USA 1 GL Ulrich Gentzel-Lingner Heidelberg FRG 306 GM Gunter Monz Peterberg Germany 3 GR Greg Roberts Kaapstad South-Africa 15 HA ? 1 HB Hermann Boehnhardt Rodental-Moenchreden FRG 973 HD ? 1 HK Horst Koehnke Stade-Elbe FRG 4717 HS Hermann Schnitzler Grevenbroick FRG 3 HVB Hendrik Vandenbruane Beernem Belgium 3 IL Inge Leyssens Edegem Belgium 1 IP * ? 1 IPO * Ian Porter Australia 1 JA Jan Aelbrecht Belgium 1 JC Johan Claes Oostende Belgium 43 JDW Jean De Weerdt Gistel Belgium 180 JDG * Don Gardner 6 JEV * Jim Varney Sacramento, California USA 84 JG * Jason Gibson Melbourne Australia 3 JH Johan Hoste Oostende Belgium 1 JHR * Jay H. Respler Freehold, New Jersey USA 122 JL Jean Lecacheux Meudon France 1 JM Jean Meeus Kessel-Lo (till 67-06-30) Belgium 1242 Korbeek-Lo Belgium Erps-Kwerps (fr 16-07-68) Belgium JN * Jim Nix Memphis, TN USA 36 JO J. Oudman Groningen The Netherlands 58 JOP Joel Piraux Marseille France 3 JP John Prentice Albuquerque, New Mexico USA 15 JPH * Jason Hatton Strasbourg France 91 JR J. Ruland Hasselt Belgium 1 JR Juergen Renn Moers FRG 1 JS Jan Strobbe Eernegem Belgium 21 JSC * Jim Scotti Tucson, AZ USA 85 JV Jaap Veltekamp Vries The Netherlands 34 Groningen The Netherlands JVB Jan Vandenbruane Beernem Belgium 1 JVS * Jan Vansteelandt Leuven Belgium 150 JVW Jeroen Van Wassenhove Nazareth Belgium 5 JW Joel Weisberg Albuquerque, New Mexico USA 1 KAH Kai Hamalainen Lappeenranta Finland 24 KB * Ken Boedt Oostende Belgium 1 KD * Kurt Dequick Bredene Belgium 284 KDL Kris Delcourte Belgium 24 KH Kevin Hestir Albuquerque, New Mexico USA 54 KJ * Kurt Jonckheere Oostende Belgium 1651 KO Kurt Osaer Bredene Belgium 51 KVG Karin Van Genegen Mortsel Belgium 1 LA Georges Lauwers Zemst Belgium 219 LB * Leo Barhorst Ede + Alkmaar The Netherlands8483 LG Lloyd R. Gibson Thallon, Queensland Australia 37 LL L. Langeville Brussels Belgium 36 LP Lieven Van Parijs Meulebeke Belgium 10 LR Leo Rajala Jamsa Finland 7 LS * Lutz Schindler Braunschweig Germany 10 LW * Leo Wikholm Helsinki Finland 115 MA D.C. Mason Tremadoc,Caernarven,Wales Great-Britain 3 MAD Madison USA? 1 MAG Mauritz Geyser South-Africa 1 MD Alistair Macdonald Toronsville Australia 4 MF Matthew Francey Mississauga, Ontario Canada 2 MG ? 3 MJ * Michel Jacquesson Sevigny-Waleppe France 44 MM * Michael M. McCants Austin, Texas USA 2704 MO Marc Moors Bonheiden Belgium 30 MPM ? 2 MR * Mike Rosseel Belgium 41 MS Markku Siljama Mantyharju Finland 1 MVP Michel Van de Putte Ronse Belgium 24 MW ? 22 MZ Grupo Espacial Mendoza Argentina 27 NB N.J. Budd UK 1 NC * Neil Clifford Oxford UK 2 PA Peter Aneca Bredene Belgium 178 PC Patrick Carpreau Mechelen Belgium 214 PDV * Patrick Devreese Moen Belgium 733 PEW Peter Wakelin Ascot, Berkshire UK 489 PIA Pieter Audenaert Gent Belgium 1 PK Petteri Kankaro Merimasku Finland 58 PM * Paul Maley Houston, Texas USA 59 PN * Pierre Neirinck Malo-Les-Bains France 1280 PP Pieter Passchijn Eernegem Belgium 2 PR Paul Roggemans Mechelen Belgium 1 PS Patrick Schmeer Saarbruecken-Bischmisheim Germany 46 PW * Patrick Wils Niel Belgium 1130 Boortmeerbeek Belgium RD Rudy Dequick Bredene Belgium 43 RE * Russell Eberst Edinburgh, Scotland Great-Britain 3240 RGL * Ron Lee Falcon USA 50 RIK * Richard Keen Coal Creek USA 5 RK * Rainer Kracht Elmshorn Germany 230 RM * Rob Matson Belmont Shore, CA USA 29 RMC * Ralph McConahy Barstow, CA USA 3 RO * Jean-Pierre Rohart Wormhout France 1149 RS * Robert Sheaffer San Jose, CA USA 6 RW * Ron Welch Watson Australia 85 SA Sacramento California USA 15 SL Stefan Lobet Kontich Belgium 1 ST San Antonio California USA 22 SW * Sue Worden USA 1 TC * Tristan Cools Brugge Belgium 3456 TD Tommy Deslijpere Oostende Belgium 30 TH Terre Haute France 2 TID Tim Daniels Edegem Belgium 13 TK Takeshi Kawabata Yokohoma Japan 46 TM ? 1 TR Tuomo Roine Helsinki Finland 5 TT Tuomas Torronen Espoo Finland 1 VAG * Vince Gardiner Australia 565 VB Isi Van den Broeck Londerzeel Belgium 686 Duffel Belgium VC Paul Van Cauteren Aartselaar Belgium 12 VG Vincent Gathot Eernegem Belgium 44 VH Luc Vanhoeck Puurs Belgium 39 VI Van Iseghem Sint-Kruis, Brugge Belgium 24 VL Frans Van Loo Itegem Belgium 1 VM Veikko Makela Helsinki Finland 1 VN Van Nuys Belgium 29 WD Werner Depoorter Halle-Zoersel Belgium 14 WH * Wim Holwerda Loon-op-Zand The Netherlands 534 WJW William J. Welker Pittsburgh USA 9 WN * Walter Nissen Silver Spring USA 229 WPK * Willie Koorts Wellington South Africa 21 WV * Willy Verhaegen Wetteren Belgium 1720 YY Yoshiro Yamada Yokohama Japan 12 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://www2.satellite.eu.org/sat/vsohp/satintro.html Kurt Jonckheere, kjon@mail.dma.be