PAGE i American Association of Variable Star Observers AAVSO SS CYGNI LIGHT CURVES 1896 - 1985 * * * AAVSO MONOGRAPH 1 This monograph is dedicated to Clinton B. Ford in recognition of his long standing support of the Association and his distinguished contributions to Astronomy. Prepared by Janet A. Mattei Michael Saladyga Elizabeth O. Waagen Charles M. Jones Funds for preparation and publication provided by Clinton B. Ford Aditional funds provided by National Aeronautics and Space Administration (NASA) International Astronomical Union (IAU) AAVSO members PAGE ii COPYRIGHT 1985 by the American Association of Variable Star Observers 187 Concord Avenue Cambridge, Massachusetts 02138 USA All rights reserved. All commercial use of any part of this book requires the written permission of the AAVSO. All non-commercial use by individuals and educators is granted without restriction. PAGE iii TABLE OF CONTENTS Foreword v Observers of SS Cygni vii Information on SS Cygni xi Key to Symbols xi Historical Light Curve of SS Cygni, 1896 - 1963 1 Light Curves of SS Cygni, 1963 - 1985 2 PAGE iv is blank PAGE v SS CYGNI LIGHT CURVES 1896 - 1985 Introduction AAVSO long-term light curves on variable stars contain crucial information that has a significant bearing on many outstanding questions in astrophysics. With cataclysmic variables, these questions include stellar instability, time-varying processes in stars (recurrence time, duration, rise and decay times, unusual changes in the pattern of events), the structure of the complex binary, accreting white dwarfs (low-luminosity x-ray sources), the dynamics of accretion in the degenerate star, the physics of accretion disks, and the problem of viscosity. In addition, the long-term light curves contain invaluable information on dwarf nova outbursts, the nature and origin of which are still not well understood. The long-term records of AAVSO will provide the basic set of observations which models of outburst phenomena in accretion disk systems must match. The AAVSO Monograph series to publish long-term data will assist in answering the questions given above. The monograph format will enable us to present the long-term behavior of these stars, with each monograph containing 20 or more years' data on one star. We have started this Monograph series with cataclysmic variables because of the high demand for data on these stars, and also because no AAVSO data on them from 1963 to the present have been published. We will later proceed with the publication of other types of stars. SS Cygni Light Curves 1896 - 1985 AAVSO Monograph 1 contains light curves of SS Cygni from its discovery in 1896 to 1985. The AAVSO historical light curve from 1896 to 1963 (J.D. 2438295) is presented on page 1. This light curve has been included to give a more complete picture of SS Cygni's behavior. The observations that comprise this light curve have been published in Popular Astronomy, Volumes 19 - 43 (1917 - 1935); Harvard Annals, Volumes 104 - 107 and 110 - 116 (1935 - 1946); AAVSO Quarterly Reports 1 - 27 (1946 - 1961); and AAVSO Report 29 (1961 - 1963). Pages 2 through 41 contain light curves from 1963 to 1985, with each dot representing one observation. Pertinent information on SS Cygni and a key to symbols in the light curves are given on page xi. A scaled grid is provided with the monograph to assist in determining the exact date and magnitude of any data point. Data are plotted Julian Date versus visual magnitude, and the start of each year is indicated along the upper axis. The observations in this monograph are the contributions of AAVSO members or observers in the United States and abroad. 832 observers have contributed over 66,000 observations to these light curves. The names and observer codes of observers who have contributed observations to this monograph are given on pages vii to x. 33 In preparing the data for publication each observation was checked for accuracy, first using a specifically generated computer program, then once again by my technical assistant Elizabeth O. Waagen, and by me. The individual observations from 1963 to 1985 included in this monograph have been preserved on computer data cards, magnetic tape, and printout. Copies of the magnetic tape or a listing of observations for further in-depth study v PAGE vi may be obtained by writing to AAVSO Headquarters. The observations before 1960 are not in machine-readable form at this time. However, we are in the process of making these observations also machine-readable. Acknowledgements Our special thanks go to Clinton B. Ford for his very generous contribution for the preparation of this and subsequent monographs. We dedicate this first monograph to him. We acknowledge with thanks the support provided through the National Aeronautics and Space Administration (NASA) HEAO-2 Guest Investigator Program (Grant NAG8-544) for the preparation of this and following monographs. Our special thanks go to the International Astronomical Union (IAU) for their support of our monograph series and for the grant provided to the AAVSO to publish this and other monographs. Our sincere thanks go to AAVSO members and friends for their contributions to prepare and publish these monographs. We gratefully acknowledge the support provided through National Science Foundation Grant AST 7910576 for computerization of a portion of the data. We acknowledge with thanks the computer support of the Harvard- Smithsonian Center for Astrophysics and the continued support of Professor Owen Gingerich and Barbara Welther. The checking of the data and the plotting of the light curves were accomplished using the computers at AAVSO Headquarters. We are indebted to the Research Corporation for the Charles H. Townes Fund grant to the AAVSO to purchase the in-house computers without which we could not prepare the monographs. Many AAVSO assistants helped in the preparation of the data for publication. Special thanks go to Michael Saladyga for preparing the data and plotting the light curves, Elizabeth O. Waagen for extracting the data from our data files containing 3,500,000 observations, and for her meticulous checking of the observations, and Charles M. Hones, AAVSO's Margaret Mayall assistant, for developing the computer programs to check the data. Robert S. Hill, Karen J. Meech, Shelly K. Pope, and Richard J. Strazdas assisted in the development of the programs to manage the large volumes of data. Barbara Silva, Bethune Kelly, and many Harvard University and Massachusetts Institute of Technology students have helped in making the data machine-readable. The dedication, the many, many hours of observing, and the untiring efforts of our observers in pursuit of contributing to variable star astronomy have made this publication possible. Our very sincere thanks and gratitude to them for their valuable astronomical contributions. Janet Akyuz Mattei Director Cambridge, Massachusetts October 1985 vi PAGE vii OBSERVERS OF SS CYGNI ABBOTT, A. PATRICK AAP BIRKNER, ALAN J. BKN ADAMS, JAMES E., JR. ADJ BLAGG, BILL BGB ADAMS, ROBERT M. AD BLAKE, HENRY BLK ADORNATO, GEORGE ADG BLIXT, RON BLR AHNERT, PAUL AH BOHME, DIETMAR BOH AKIYOSHI, TARO C. AYT BOHN, DENNIS BOD ALBRECHT, WILLIAM B. AB BOINCK, F. BFK ALDERING, GREGORY S. ALS BOIS, BERNARD BOI ALLIN, ROBERT AG BORGMAN, MARK W. BMW AMBROSE, K. SCOTT AMB BORNHURST, LARRY BOR ANDERER, JOSEPH A. AJ BORTLE, JOHN BJN ANDERSEN, ODD'IVAR AOD BORTLE, JOHN E. BRJ ANDERSON, CARL A. AK BORZELLI, CARMINE BZC ANDERSON, CURTIS E. AC BOUMA, R. J. BMU ANDERSON, ROBERT ANR BOWDEN, JAMES L. BJL ANDERSON, STERLING ASR BOWERS, JAMES E. BJE ANDRESS, J. ROBERT AJR BRADLEY, PHILIP A. BAP ANDREWS, RICHARD AWR BRAINARD, DAVID M. BDM ANNAL, ROBERT J. ANN BRAM, ERIC BRE ARIAIL, ROBERT B. ARI BRANCHETT, DAVE BDT ARMSTRONG, C.P. ACP BREMSETH, PER-JOHNNY BMS ARNOLD, LUC ARN BRETL, THOMAS C. BTB ARTHUR, PHILIP APL BRIL, HENK BHN ASBJORN, BREIVIK BAV BRIN, DAVID BDV ATKIN, TIM AKT BRITISH AST. ASSOC. BAA ATKINSON, H.C. AHC BRLAS, PAL BLP ATWOOD, PHILIP F. ATW BROOKS, JAMES E. BRK AUBAD, J. AUB BROWN, DOUGLAS BRH AUCOIN, DONALD, JR. ADE BROWN, LAUREL BRZ BAKER, TIM R. BTR BROWN, NICHOLAS BNK BALDWIN, JOHN RAND BLJ BROWN, TIMOTHY BRT BALDWIN, MARVIN E. BM BRUNER, F. D. BFD BALLEGOY, E.V. BVE BRUNO, ALAIN BOA BANKS, JAMES BJ BRUTON, JIM BJM BARBIN, WADE BBN BRYAN, JAMES T., JR. BRY BARKSDALE, WILLIAM BWK BRYDEN, ROBERT BYD BARNHART, STEPHEN F. BSF BRYDGES, JEFF BJY BARONI, SANDRO BSR BUCARO, STEVE BS BARR, KEVIN P. BAK BUCKSTAFF, RALPH N. BC BARTLETT, LEONARD A. BLA BUENO, ANTONIO T. BUO BATES, NEIL BNE BUHROW, RUSS BUW BAUER, JOHANN BAU BULDER, H. J. J. BDH BAXTER, JOHN BXJ BURT, STEPHEN E. BX BEAMAN, ALAN BAE BUTLER, HERBERT BTL BEAMAN, BARRY B. BBA BUTLER, THOMAS BUL BEAMAN, CAROL J. BCJ CALDER, JOHN B. CDE BEAMAN, KELLY E. BKY CAMPNEY, WALTER CWA BEAVER, JOHN BEJ CANADA, EDWIN R. CAN BECK, INEZ BEK CANDELA, JOSEPH CEA BECKMAN, KENNETH BKK CARLSSON, MATS CRL BEDIENT, JAMES R. BJS CARPENTER, CLAUDE B. CE BELL, ROSS E. BSE CARPREAU, PATRICK CPK BENEDICT, BRAD BCB CARTER, BRIAN A. CTB BENNER, TERRY BTY CASPER, ALLEN A. CSA BERGER, L. BEG CAVAGNA, MARCO CIT BERNSTROM, MARVIN L. BML CERAR, JOZE CJZ BERRIOT, M. BIO CHADWICK, RICHARD CDR BERTWELL, CHARLES D. BET CHALOUX, DAVID A. CDX BILODEAU, GERALD. A. BIL CHAPLE, GLENN, JR. CGF BIRIOUKOFF, GEORGES BIK CHASE, LOIUS E. CLU CHEW, ROBERT L. CHW DRALLE, ANTHONY V. DRA CHILDRESS, R. KEN CRK DREILING, MARK J. DMJ CHOATE, ROBERT CHR DUCOTY, RICHARD DRY CICCONETTI, JIM CIC DUDLEY, R. R., JR. DRR CLANCY, SEAN CLL DURKEFALDEN, MANFRED DKF CLANCY, STEPHEN CLY DURUY, MAURICE V. DUR CLARK, WAYNE CLK DUVILLIERS, ERIC DEU CLARKE, IAN CKI DVORAK, SHAWN DKS CLEMENT, EDWARD W. CEW DYCK, GERALD DGP CLYDE, ROBERT CLB EAST, GEORGE EG COCHRAN, HARRY D. CCR ECKENDORF, JAMES H. ECJ COLE, ANN CLO ECKERT, CHRISTOPH ECK COLEMAN, DONNIE S. COD EDELSTEIN, MARK S. EMS COLLINS, M. J. CMJ EHRHART, EDWARD EHR COLLINS, PETER L. COL ELIAS, DEMETRIUS P. ELD COMELLO, GEORGE CMG EMERSON, GARY P. EM CONGER, DARRELL CD EMMERT, JOHN T. EJT CONNORS, MARTIN G. CNS ENSIGN, ROY K. ERK CONSTANZO, DANIEL CSD ERICSSON, CARL A. ERC COOK, LEWIS M. COO ERIKSSON, SOREN EKS COOK, RYAN D. COK EVERAERT, JEAN LUC EJL COOK, STEPHEN P. CK FARRAR, WALTER, JR. FRW COOKE, S. R. B. CO FAUSEL, CHARLES A. FCA COOPER, CLAY CCL FEIJTH, HENDRIK FJH CORTESE, BERNARD CRB FERENCE, ALAN M. FEA CORTNER, DAVID CRN FERGUSON, HENRY FEH COTEFF, CHRIS CCH FERNALD, CYRUS F. FE COULOMBE, ANDRE CDA FERREIRA, JAMES L. FJL COX, LOUIS B. CLX FETTERMAN, THOMAS I. FET CRAGG, THOMAS A. CR FINK, CHARLES L. FK CROSS, DARRELL CDS FINKE, BARBARA FIN CRUMRINE, ROBERT CRR FINKE, CARL FIC CUNNINGHAM, DOUG CUN FITZGERALD, D. J. FG DANKO, JANOS DAN FITZGERALD, KEN FGK DANSKIN, KEITH H. DAK FLORKOWSKI, DAVID FS DARNELL, PER B. DN FLYNN, EDWARD M. FEM DARVANN, TRON A. DTA FOOTE, BYRON FOO DAVIDSON, GREG DV FORCZYK, STEPHEN FZS DAVIDSON, ROBERT DRB FORD, CLINTON B. FD DAVIS, JACK DAJ FORMA, JAMES FOJ DAVIS, RICHARD H. DRH FORS, TORRE FTO DAWSON, DENNIS W. DWN FORTIER, GEORGE L. FT DE FORGE, W., JR. DWM FRANK, PAUL K. FPK DE MENTEN, TH. DMT FRICH, A. FRH DE YOUNG, JAMES A. DEY FRIEDMAN, DAVID M. FN DEBOOSERE, FRANK DBF FRIGON, LEON A. FRI DECEUNINCK, STEFAAN DES FRITON, EDWIN E. FR DENTIGER, RONALD DTR FULLER, DALE B. FLR DICKINSON, R. T. DT GAERTNER, ELKE GAE DICKINSON, WILLIAM DIK GALDUN, DAN GAD DIEDRICH, DELORNE DHD GARASICH, JAMES W. GJW DIEDRICH, GEORGE DHG GARDNER, ROBERT J. GDR DIERICK, DOMINIQUE DMN GAREY, PATRICK GAA DIETHELM, ROGER DRG GARNAVICH, PETER GAP DIXON, JAMES DIX GARRISON, JAMES L. GJS DIXON, ROBERT DRX GARSZTKA, J. P. GAZ DOERR, CHARLES DCH GAUGHRAN, HAROLD L. GHL DOMBROWSKI, PHILIP DPL GAYDOS, MARK GAY DOMEN, RONALD DMR GESCHWIND, RALPH GSR DOMENY, GABOR GDB GIANNOTTA, GIORGIO GGI vii PAGE viii GILCHRIST, ROBERT S. GCH HONNART, FREDERIC HON GILL, DAVID GDI HOOGEVEEN, GEERT HOO GIORDANO, JAMES GRJ HOPP, ULRICH HOP GIULIANI, VALTER GVT HORTON, IDA HTI GLENN, FLORENCE GLF HORVATH, ISTVAN HOI GLENN, WILLIAM H. GLW HOSSFIELD, CASPER H. HSF GLIBA, GEORGE W. GLG HOSTE, SERGE HSR GLOMSVOLL, ARNE GAV HOUGH, DAVID HOU GOFF, BILL GFB HOUSTON, WALTER S. HU GONDOLA, ANTHONY E. GDA HOWARTH, IAN D. HOW GOODELL, DAN GDD HOWELL, ANDY HOA GOODWIN, JENNIE GJR HOYLE, S. J. HOY GOODWIN, PAUL N. GOP HOYNOS, JOHN F. HYJ GORSKI, LARRY M. GLM HUBBARD, RT. REV. R. HUB GOUGH, THOMAS GGH HUDSON, JEROME A. HJA GRAHAM, KEITH A. GKA HUGHES, H. L., JR. HUH GRAHAM, KENNETH GRK HUGHES, CHARLENE HUG GRANSLO, BJORN H. GRL HUGHES, DONNA J. HUO GRANT, JEFFERSON H. GJH HURLESS, CAROLYN HR GRASSHOFF, E. RAY GAS HURST, GUY M. HUR GREEN, DANIEL W. E. GRW HUTTER, DONALD J. HTD GREGORY, GGY IADEVAIA, DAVID S. IDG GRIESE, JOHN W. III GRI IDEM, MICHAEL IML GROSSMAN, ARNOLD S. GA ISLES, JOHN E. ILS GRUNNET, C. GCT ITO, MASAYUKI ITO GRZELCZYK, HEINZ GRZ IZUMO, AKIKO IAZ GUALDONI, CARLO GCO JACKSON, C. J. JKS GUGUMUS, V. GUG JACOBS, TOM JCT GUNTHER, J. GUN JAEGER, GREGG JAG HAGER, TIMOTHY HTY JAMES, PETER R. JPR HAGLUND, MICHAEL E. HAG JAMES, ROBERT A. JM HALBACH, EDWARD A. HK JEFFREY, J. THOMAS JJT HALL, MARK A. HMK JENSEN, K. KLINDT JKK HAM, RONALD HMR JOHN, W. RANDY JWR HAMPTON, WALTER R. HP JOHNS, MIKE JHN HANNON JAMES HAN JOHNSON, GUS E. JOG HANON, CHRISTIAN HNN JOHNSTON, ROBERT B. JT HANSON, GENE HSG JONES, MICHAEL I. JNM HANSTEEN, VIGGO HVG JONES, ROBERT JOR HARLES, PETER HLP JORDAHL, DAVID JRD HARRINGTON, PHILIP HRR JORDAN, JERRY JJN HARTIGAN, PATRICK M. HAT JURY, ROGER JRR HARTMANN, FERDINAND H JUSTISON, DENNIS L. JDL HARVAN, RICHARD P. HAV KANE, PHILLIP KPS HATAI, ERNIE HAE KARBERG, WAYNE KAR HAWLEY, WALTER HWL KELLEY, GEORGE, JR. KLY HAYDEN, EDWARD R. HAY KERLEY, LLOYD, JR. KLD HAYS, ROBERT HAB KESLER, TERRY KTY HAZEL, LAWRENCE HZL KESZTHELYI, SANDOR KSZ HEASLEY, ALLEN S. HY KIEHL, MATTHIAS KIM HEASLEY, MRS. B. L. HYB KIMBALL, MAXWELL KBM HEASLEY, THOMAS A. HYT KIMBALL, STEPHEN O. KMB HEIFNER, MARK A. HEF KING, ROBERT P. KRB HEINTZ, J. HEI KIRBY, PHILLIP E. KIR HEISER, ERWIN HEE KIRBY-SMITH, H., JR. KBS HEITZ, MARTY HTZ KLEBERT, KLAUS KLK HELBAK, KNUT HEL KLINTING, OLE KON HENDERSON, RONALD HZ KLINTING, HENNY KHT HEYNDRICKX, BRUNO HEY KNIGHT, GEORGE KGT HIETT, LANCASTER HE KNIGHT, STEPHEN P. KSP HIGGINBOTHAM, NORMAN HIN KNOX, OSWALD J. KOJ HILL, RICHARD E. HRI KNUPP, PAT KPP HILL, RICKY L. HIL KOCSIS, ANTAL KOC HOGAN, MICHAEL E. HGM KOEHLER, KARL F. KKF HONDA, HIDEO HOH KOHL, GOERGE KLG KOHL, MICHAEL KHL LOSO, FRANK G. LOF KOKKINEDIS, AKIS KAS LOVETT, JAMES LVT KOLLER, HERBERT J. KHJ LOW, JAMES LOJ KOLMAN, ROGER S. KRS LOWDER, WAYNE M. LX KOMOROUS, MIROSLAV KMA LOWRY, WILLIAM I. LW KOREN, MICHAEL KOM LOZAR, ROBERT C. LZR KORYKANSKY, DONALD KCY LUBCKE, GILBERT C. LBG KOSA-KISS, ATTILA KOS LUCAS, MRS. JAMES LS KOVACS, ISTVAN KVI LUDWIG, CLUYSE LCG KRIDLO, THOMAS N. KRD LUKAS, RAINER Z. LKS KRISCH, GUNTHER KIS LUNSFORD, ROBERT LRE KRISCIUNAS, KEVIN L. KRK LUURS, J. O. LJO KRUSZKA, JOHN S. KRZ LYNCH, RICHARD F. LYR KRUTA, JAROSLAV KRU LYNK, WILLIAM LYW KUHNS, JAMES L. KUH MAAG, RUSSELL C. MAA KUIPERS, GAUKE KPG MACH, WILLIAM, JR. MWT KUPLINSKI, R., JR. KUR MADDEN, PATRICK J. MDD KUTNJAK, ZORAVKO KZO MAHNKEY, C. PATRICK MAN KUWABARA, TAKEHISA KUW MALLAMA, TONY MLT LA FORTUNE, EDWARD LFE MANN, REV. GARY L. MGL LA PRATH, JAMES LPT MARCARIO, MIKE MCO LACASSIN, GILBERT LGT MARCEY, BRIAN MBA LACY, H. J. LCH MARISKA, JOHN MRJ LAFONTAINE, GERRY LAG MARTER, WAYNE MAW LAMBERT, RANDY LAR MARX, HARALD MRX LANDLESS, VAUGHAN LAN MASCOLA, KEN MSK LANGE, HERBERT A. LGH MASSEY, PHILLIP MSY LANGHANS, THOMAS W. LTW MATEO, MARIO MTO LASKOWSKI, THOMAS M. LTM MATSUYAMA, HIROSHI MTH LAUER, TOD R. LUT MATTEI, JANET A. MTT LAURENT, BERGER LAB MATTEI, MICHAEL MTM LAURENT, DIRK LDR MATYAS, CSUKAS MCU LAVERY, RICK LVR MATYI, STEPHEN MTY LAWRENCE, PATRICIA LAW MAVROFRIDIS, GEORGE MGE LAWRY, THOMAS F. LYT MAYALL, MARGARET W. MA LAWSON, MIKE LWS MAYER, ERNST H. MYR LEAKE, DAVID C. LKD MAYER, ERNST W., JR. MYW LEBERT, ROLAND LEB MAYER, JAY W. MJW LECVONA, ADOLFO LCA MC CALLUM, ROBERT MCB LEIFSEN, TORBEN LTF MC CONNELL, MARK MOM LEITNER, ROBERT A. LER MC FARLAND, TOM MCF LEMBREE, ROBERT LRB MC GINNIS, GARY MGG LENSS, IVARS LNS MC INNERNY, BRIAN J. MCI LENZ, GEORGE LNZ MC KENNA, JEROME MKJ LEPPER, G. H. LEP MC KEOWN, KEVIN M. MKK LERUIK, ROLF LEK MC MILLAN, BETTY MBC LESTER, DANIEL LES MC PHERSON, C. A. MP LEVESQUE, ADRIEN LAJ MEANS, DENNIS L. MSD LEVY, DAVID H. LVY MEDIAS, IVAR B. MIB LEY, FREDERICK LEF MEDWAY, KENNETH J. MED LIMA, ROY A. LIM MEGGINSON, D. L. MDG LIMBURG, ERIC LBE MEIER, ROLF MEI LINAMEN, CHRIS LNM MENOHER, PEARSON MEN LINDBLOOM, GEORGE G. LNB MENZIES, KENNETH T. MZK LINGAS, JACOB LJK MEZOSI, MR. CSABA MEZ LIVINGSTON, DONALD LI MIDTSKOGEN, ORNULF MOK LOCHER, KURT LK MIKEL, ALAN MKA LODGE, JAMES LOG MILLER, MARTIN P. MKM LONG, JAMES LGJ MILLER, WILLIAM A. MWA LOPATYNSKI, GARY V. LGV MILTON, RUSSELL MTL LORENZ, ERNEST O. LZ MIMNA, ROY A. MMA LORING, DANIEL P. LRD MINER, JAMES R. MJI LORSIGNOL, JEAN LOL MINOIS, JOEL MIS LORSIGNOL, SERGE LOS MINTER, TODD MTD LOS, EDWARD J. LEJ MISHLER, JERALD R. MJR viii PAGE ix MITCHELL, ROBERT C. MTC PAUL, ROBERT PAL MIZSER, ATTILA MZS PEARCE, ERIC C. PCE MOCHIZUKI, ETSUIKU MCE PEARLMUTTER, ARTHUR PN MOGELINSKI, JERRY MGJ PEARLMUTTER, JOAN H. PJW MOHRBACHER, DAVID MOD PEATTIE, NOEL PTI MOLNAR, JAMES, JR. MOL PECK, CARL R. PCR MONELLA, RINALDO MAR PEDERSEN, EIGIL PEI MONGER, DON R. MDE PEGUET, CLAUDE PEG MONIOT, PHILIP MPT PELTIER, LESLIE C. P MONSKE, ROBERT L. MOR PENN, MATTHEW PNM MONTAGUE, ALLEN C. MJ PERALA, MARTTI PMR MONTAGUE, FREDERICK MF PEREZ, ALAIN PZA MOORE, PATRICK MOP PERRY, GLENN PGL MORBIDELLI, A. MAO PESCI, FRANK PFK MORGAN, FRNACIS P. MM PESCI, STEFANO PSO MORGAN, JAMES E. MOJ PETROHAN, BETTY PNB MORRIS, CHARLES S. MRR PETTENGILL, DWYNAL PED MORRISON, PATRICK D. MRO PFEIFFER, GERHARD PFF MORRISON, WARREN C. MOW PHILLIPS, J. F., JR. PHJ MUIRDEN, JAMES MRD PIDILLA, STEVE PAS MULLIGAN, F. KIRBY MFK PITCOVICH, GEORGE O. PGO MUNSTERMAN, H. MHN POITEVIN, PATRICK PTP MURN, PAUL MUR POLSON, ED. PLE MURPHY, MICHAEL J. MJC POWASKI, RONALD E. PWR MURPHY, MIKE MUM POWELL, EUGENE A. PO MUZINUCH, RICHARD P. MRZ PRICE, CAROLE M. PRC NADEAU, LAWRENCE B. NL PRICE, FRANCIS J. PFJ NANESON, JOHN NNJ PRICE, LELAND H. PRI NEDERLAND VER. STR. NDR PROVIN, ROBERT PR NELSON, GEORGE T. NEL PTACEK, KIM E. PTF NELSON, ROBERT H. NRH PUGET, ALFRED PGA NEMETH-BUHIN, AKOS BAO QUESNELL, TOM QTL NEWBERRY, MARK NM RALEY, MIKE, JR. RMJ NEWBERRY, MICHAEL V. NEW RAMSEY, MICHAEL L. RMM NGUYEN, JEAN-JACQUES NGU RANDALL, EVERETT Z. REZ NIELSEN, JOSEPH A. NJA RAPHAEL, ROBERT B. RRB NIELSEN, VILLY G. NVG RAVER, DOUG RVD NISHIMURA, KEN NIK RAWSTRON, G. O. RW NORDBY, JOHN M. NBY RAYMON, KEN RYK NORDEN, RODNEY A. NN RAYNOR, LYNN O. RNR NORTON, THOMAS S. NTS REHNER, DAN REH OBERSTATTER, A. OF REINHART, CHARLES C. RNT OLESEN, J. O. OJO RENNER, CARL J. RCJ ORAVEC, EDWARD G. OV RENNER, THOMAS RNN ORTEGA, GIL OGJ RIETH, RALPH RIR ORTWIEN, DONALD A. ODA RIGGS, JOHN L. RJI OSORIO, JOSE RIPERO OJR RIOPKA, TERRY RTK OSTERMANN, ALEXANDER OSA RIPPEL, MORRIS RIP OTTUM, BRIAN D. OTB ROBERTS, HARRY V. RH OVERBEEK, M. DANIEL OB ROBOTHAM, ROBERT A. RAR O'BREZA, SCOTT OBR ROCHE, HYMAN RHY O'BRIEN, GERALD OBG RODUTA, PETER G. RPD O'BYRNE STEWART L. OBS ROESS, STEVEN T. RSS O'CONNOR, STEPHEN D. OCN ROMANUCCI, JAMES ROM O'MEARA, STEPHAN OME ROSEBRUGH, DAVID W. RB PALLAT, EUGENE A. PEA ROSENFIELD, C. RNC PALOMBO, STANLEY PSA ROSENFIELD, D. A. RND PANKE, MISS DALE PAD ROSS, GARY M. ROG PAPP, SANDOR PPS ROSS, HUGH ROH PARMENTIER, RONALD PRL ROYER, RONALD RR PASTORE, PETER F. PSP RUMBALL-PETRE, HUGH RPH PATRICK, RAYMOND PRN RYAN, JOHN RYJ PATTEE, ALAN M. PAA RYAN, PHILIP J. RPJ PATTERSON, CRAIG PAC SABIA, JOHN D. SJD PATTERSON, RUSSEL H. PAR SABINE, KENNETH M. SAB SACCONE, DONALD SCD STEFFEY, PHILIP C. STI SAGODI, TBOLYA SGT STEGMANN, PAUL SGP SAKARIAS, MICHAEL SKM STEPHAN, CHRIS SET SAKUMA, SEI-ICHI SSU STEPHANOPOULOS, G. STF SALADZIUS, ROGER SZR STEWART, R. S. SWS SALTZMAN, TORBJORN SAZ STEWART, ROBERT N. SR SAMOLYK, GERRY SAH STIEGLER, MICHAEL SGL SANDEL, JEFF G. SNL STINSON, TOMMY STT SARRAFIAN, HARRISON SRH STOIKIDIS, NIK STQ SATOSHI, AKITA ASK STOKES, ARTHUR J. SAJ SAUNDERS, MARK SAU STONE, P. MICHAEL STO SCANDINAVIAN AST. S. SAS STOUT, ROY STZ SCARL, JAMES D. SCC STRATER, JACK L. SJL SCATLIFF, JOHN SCJ STRITOF, NIKOLAJ SNJ SCHAEFER, BRADLEY E. SCK SUGARMAN, MICHAEL D. SGM SCHAUPP, RICHARD W. SRW SULLIVAN, CHARLES E. SUL SCHMIDT, JOACHIM SIJ SULLIVAN, PHILIP SPP SCHMIDT, ROBERT H. SRD SURAWSKI, URSULA E. SUR SCHMITZ, PAUL F. SPL SVENTEK, PAUL SVN SCHMITZ, VICKI SV SWOBODA, ANITA SWO SCHROYENS, ANN SCY SZANTHO, LAJOS SOZ SCHROYENS, DANIEL SDH SZEGEDI, BELA SZG SCHWEITZER, EMILE SCZ SZENTMARTONI, BELA SZC SCOVIL, CHARLES E. SCE SZOKE, BALAZS SKB SEALY, ROBERT N. SL SZYBOWICZ, THEODORE SZY SEARS, KAY G. SEK TABOADA R., DOMINGO TB SEIDENSCHWARZ, DALE SEI TAKATS, PETER TAK SEIFERT, EDWARD H. SEE TALAGA, ROBERT TLR SESSIONS, LARRY SES TAYLOR, PETER O. TAY SHARPE, STEVEN SHS TANZER, RICHARD TZR SHEAFF, RANDOLPH SFR TAYLOR, DONALD R. TDR SHERROD, CLAY SHB TAYLOR, LEE R., JR. TYL SHINN, B. FRANKLIN SBF TAYLOR, MARY JANE TYR SHORTEN, ANDREW J. SJA TEMPLICZKY, ISTVAN TPS SHOTTER, LAWRENCE J. SLH THIBAULT, GUY THG SIMMONS, KARL SKL THIBEAULT, DORIS TBD SIMMONS, NEIL A. SNE THOMAS, ANDREW TAS SIMMONS, WANDA SKW THOMAS, HOWARD D. TM SIMPSON, A. PHILLIPS SPN THOMAS, JAMES TJ SKINNER, C. R. SKN THOMAS, JOSEPH V. THM SKOTTEGARD, PETER N. SKT THOMAS, MORGAN A. TMA SLACK, LEONARD L. SLL THOMAS, RON P. TMR SLAUSON, DOUGLAS M. SDN THOMPSON, DANIEL THD SLOCUMB, ROBERT C. SLO THOMPSON, MICHAEL E. TME SMALL, BRUCE SLB THOMPSON, RAYMOND R. THR SMITH, ALAN L. SMI THOUET, BERNARD THU SMITH, DOUGLAS SMD THURRELL, MALIN V. TMV SMITH, HORACE A. SHA TIC, BOJAN TBC SMITH, J. RUSSELL SJ TOLGYESI, ANTAL TAN SMITH, LARRY D. SLD TOONE, JOHN TOO SMITH, MICHAEL B. STL TORRES, EDUARDO TCE SNOW, DAN E. SO TOWNSEND, A. WAYNE TWN SODER, JAMES SOD TRANK, RANDY TRY SOUTHWICK, ROBERT G. SOU TROIANI, DANIEL M. TDM SPECHT, MILES SPM TROMMER, DIRK TRR SPEIL, JERZY SJZ TRUAX, JON C. TJC SPELL, CHESTER S. SPC TUBOLY, VINCE TUB SPONGSVEEN, JUL SPO TULLOCH, MITCHELL K. TUL SPRATT, CHRISTOPHER SC TYSON, RICHARD L. TYS SRELZER, HAROLD J. SZH UNDERHAY, G. ERNIE UND STANTON, RICHARD H. STR VACQUIER, VICTOR VAQ STARUK, WALTER E. STU VADASZ, SANDOR VAD STEARNS, ALLEN STA VAIDIS, JEAN PIERRE VAI STEBLINA, VLADIMIR SVD VAN CAUTEREN, PAUL VCP STECKNER, THOMAS K. SKS VAN ORSOW, DOUG ODV ix PAGE x VAN WASSENHOVE, J. VWS WALKER, WILLIAM WSE VANDERVOORDE, J. VJD WALLS, HOY J. WLL VANIER, PIERRE VNL WARDEN, RANDY WRN VANMUNSTER, TONNY VMT WARMERDAM, J. WMJ VEDRENNE, PAUL VED WARNER, BIAN D. WAB VELASCO, P. Y E. VEL WASHBURN, WILLIAM A. WWA VELDE, W. V. D. VWD WASSON, NORMAN F. WNF VERDENET, MICHEL VET WATANABE, AKIRA WAT VERNA SEVERINO VSE WATERS, FLOYD H. WTF VIALLE, JACQUES VIA WEBB, WILLIAM V. WBB VINCI, GREGORY VGJ WEBER, DONALD F. WBD VISOCKI, GARY VIS WEBER, JAMES W. WEB VLASIC, JOHN C. VJC WEBER, RICHARD J. WER VOLKMER, KENT VOK WEBSTER CHARLES B. WCB VOLLMAN, WOLFGANG VOL WEIER, DAVID D. WEI VUYLSTEKE, PIETER VYP WEINER, WILLIAM WIW WALES, THEODORE WTH WELLS, ANDREW WEA WALKER, PAUL WKP WEND, RICHARD E. WC WERNER, JAMES WRJ WITTEN, BLAKE C. WTN WERNER, WILLIAM WRW WOHLEVER, RICHARD A. WHR WESOLOWSKI, MIKE WEM WOHLEVER, TOM WHT WEST, FREDERICK WEF WOLPERT, BOB WBT WEST, JOHN WTJ WOMACK, CAROLYN L. WCL WHITEHEAD, JAMES M. WJ WOODS, NANCY WDS WHITTEN, MICHAEL WMN WOOTEN, J. WAYNE WJW WILLIAMS, DAVID B. WI WRIGHT, F., JR. WFJ WILLIAMS, DEBRA J. WDJ WUNDERLICH, MAURICE WU WILLIAMS, THOMAS R. WLM YOUNG, KEN YOU WILS, PATRICK WLP YOUNG, ROBERT R. YON WILSON, ALAN WLA ZAJACZ, GYORGY ZAG WILSON, JAMES A. WJA ZALEZSAK, TAMAS ZLT WILSON, KENNETH WLN ZANDER, ERNIE ZN WILSON, THOMAS A. WTA ZANOTTA, MAURO ZAM WILSON, THOMAS W. WSN ZELLER, PAUL A. ZPA WINGATE, BRUCE WNB ZIMMERMAN, DENNIS ZMM WISE, J. D. WIE ZIT, RAY ZT CONTRIBUTING ASTRONOMICAL ORGANIZATIONS Association Francaise des Observateurs d'Etoiles Variables (France) Astronomical Society of Southern Africa, Variable Star Section Astronomischer Jugendclub (Austria) Berliner Arbeitsgemeinschaft fur Varanderliche Sterne (West Germany) British Astronomical Association, Variable Star Section (England)--(BAA) Japan Astronomical Study Association Nederlandse Vereniging voor Weeren Sterrenkunde, Werkgroep Veranderlijke Sterren (Netherlands)--(NDR) Norsk Astronomisk Selskap, Variable Stjernegruppen (Norway) Pleione Valtozocsillag-eszlelo Halozat (Hungary) Royal Astronomical Society of Canada Scandinavian Astronomisk Selskap--(SAS) Vereniging Voor Sterrenkunde, Werkgroep Vanderlijke Sterren (Belgium) x PAGE xi INFORMATION ON SS CYGNI Right Ascension Declination Position: (1900) 21h 38m 47s +43o 07.7' (1950) 21 40 45 +43 21.4 (2000) 21 42 42 +43 35.0 Type: Cataclysmic variable - dwarf nova of U Geminorum type Average Outburst Frequency: 50 days Orbital Period: 0.275130 day (6h 36m 11s) Spectra (secondary): K5V Mass Ratio (primary/secondary): 1.70 +/- 0.04 Mass (primary): 1.33 Mo Mass (secondary): 0.80 Mo +/- 0.10 Inclination: 38 degrees Other Information: x-ray source (hard and soft x-ray) KEY TO SYMBOLS Symbols used in this monograph are: . = 1 observation v = variable is fainter than magnitude indicated on light curve (variable not seen) PAGE xi