THE OBSERVATION AND ANALYSIS OF LUNAR OCCULTAT IONS OF STARS WITH AN EMPHASIS ON IMPROVEMENTS TO DATA ACQUISITION INSTRUMENTATION AND REDUCTION TECHNIQUES By GLENN H SCHNEIDER A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY UNIVERSITY OF FLORIDA 1985 , This work is dedicated to Rose WeniQ and Al i ce Schne i der my late, beloved grandmothers ! I -f the stars should appear one night in a thousand years, how would men believe and adore; and preserve -for many generations the remembrance o-f the city o-f God which had been shown "Emerson", Nature; Addresses, and Lectures ACKNOWLEDGEMENTS The debts accrued at the successful completion of any endeavor which spans a number of days requiring four digits to count are many and varied. This work is no exception. Without the input and influence of many people the task which was set before me could never have come to fruition. On two levels, both personal and professional, my thanks go out to all those who helped make this project possible. The task of acknowledging all those who contributed to this study is formidable, and indeed if properly done would fill volumes. To those whom I may fail to personally acknowledge here, I offer my apology, for there are uncountable numbers who have contributed either directly, or indirectly to this study. To my parents, my grandfather Max Wenig, and grandmothers, Rose Wenig and Alice Schneider, I owe a debt which I can never hope fully to repay. With their love and encouragement, I was raised in an atmosphere which nurtured my intellectual curiosity. I was never denied the opportunity to explore, and to grow in any direction my i nqu i si t i veness had taken me. To them go my most profound gratitude, respect and love. To my committee chairman, John P. Oliver, go my warmest thanks for first suggesting this course of investigation. i v Without his assistance and guidance throughout my years at the University of Florida, this dissertation would never have been. I also thank my other committee members, Heinrich K. Eichhorn, Howard L. Cohen, Haywood C. Smith, and Ralph 6. Sel -fridge, -for their help, valuable suggestions, and at times much needed criticisms as this study progressed. To the latter, and to the University's Center for Intelligent Machines and Robotics I offer additional thanks for securing the use of the computational resources required for this investigation. I would also like to thank Ben Adenbaum and Warner Computer Systems, Inc., for granting the use of their facilities during the early stages of this project. My personal thanks extend to Frank B. Wood, and Kwan-Yu Chen, both of whom often provided much needed information related to this study. In addition, through their efforts I was afforded the unique opportunity to hone my fledgling skills as an instrumentalist by actively working on the development of the South Pole Observatory. My fellow graduate students proved to be a source of a wealth of information and ideas. To them I offer not only my thanks but the hope that there may indeed be life after graduate school. In particular, I would like to acknowledge the support I received from Roger Ball, Joseph T. Pollock (who have already realized this hope), and Gregory L. Fitzgibbons. To Elaine Reeves, who soon will enter into indentured servitude as a graduate student herself, go my thanks -for proo-f reading the manuscript o-f this dissertation, and -for helping "bag" Pallas. For their -fabrication o-f the mechanical components required <o-ften on a moment's notice) in support o-f the occultation program, I am grate-ful -for the work done by Harvey Nachtrieb and the machinists in the Department o-f Physics. Though still new to the Astronomy Department, Donald McNeil has been an outstanding asset during the latter staoes o-f this project. I o-f-fer him my personal thanks, and a tip o-f the hat -for his help with the 1984 annular eclipse, and -for Ceres as wel 1 . I would like to thank Marie Lukac o-f the United States Naval Observatory, David Dunham and the International Occultation Timing Association, and Robert Mill is at Lowell Observatory -for providing the occultation predictions used in planning the observing programs. On a number o-f personal notes I would like to express my gratitude to Alan Nathans -for his support and encouragement during my childhood. Also extended are my thanks to the members o-f the Amateur Observers' Society o-f New York, -for helping to lay the foundation -for my -future work. To Susan Howard goes my deepest appreciation -for her un-f ailing encouragement during my early years in Florida. I must also thank Laura E. Kay, who i s at this very moment spending a long, cold winter at the South Pole, -for her prodding and nudging me to -finish this thing and get out o-f Florida. v I To William Till chock (whereever he may be) I say thank you -for introducing me to APL, one o-f the major tributaries o-f my life. And I thank to Kenneth E. Iverson -for inventing what very well may be the most beautiful, aesthetically pleasing, and incomparably useful symbolic notations ever conce i ved. Finally, I thank -from the bottom o-f my heart Karla Rahman for her love and understanding during the 25-hour days and 32-day months while this dissertation was being prepared. Though to her I now say "I will", by the time this work is shelved I intend to say "I do". v I I TABLE OF CONTENTS ACKNOWLEDGEMENTS i v LI ST OF TABLES x i i LIST OF FIGURES xvii ABSTRACT xxv CHAPTERS I INTRODUCTION 1 1 Lunar Occul tat i ons: A Historical Synopsis Information Which May Be Learned From the Analysis of Lunar Occul tations 3 Goals o-f the Program of Occul tat ion Observat i on . .5 II INSTRUMENTATION 8 Opt i cal Equ i pment 8 The Seventy-Six Centimeter Telescope 8 Location and description 8 The telescope light baffle 8 Photoel ec tr i c Photometers. 13 The Astromechan i cs photometer 18 Opt i cal f i 1 ters 1? The portabl e photometer 20 Data Acquisition Electronics 20 The SPICA-IV/LODAS System 20 Design criteria for a new SPICA 20 The SPICA-IV digital electronics 22 Anc i 1 1 ary equ i pment 27 Power suppl i es. 23 SPICA-IV system configuration 29 Portabl e use .2? An a 1 og E 1 e c t r on i c s 40 The WWVB receiver 40 Radi o antennas 4? The photometer amplifier 50 Limitations of the Occul tation Photometric System 52 The Lunar Occul tat ion Data Acquisition System Sof tware 55 Software Design Considerations 55 System t imi ng 56 Memory usage 57 VIII Suplementary program documentation 58 62 Per i pheral Input/Output User (Observer) I/O 62 The video "strip chart recorder" 71 73 Data arch i val III NUMERICAL MODELING OF LUNAR OCCULTATIONS 76 The Physical Characterization o-f an Occultation Intensity Curve......... 76 The Generation o-f a Model Occultation Intensity Curve 78 Monochromatic Point Source Approximation 78 Lunar Limb Effects 79 A Monochromatic Extended Source and Limb 31 Darken i ng Polychromatic Intensity Curve 36 The E-f-fects o-f Discrete Modeling 90 The E-f-fects of Instrumental Optical Response ... .91 The Polychromatic Extended Source Intensity Curve 93 Model s o-f Doubl e Stars 94 The Di -f-ferent i al Corrections <DC) Fitting Procedure 96 A Note on Time 96 Choosing Initial Parameters -for the DC Procedure 97 Parametr i c Adjustment 100 The DC Fitting Procedure -for Close Double Stars ~. 103 Validation o-f the Fitting Procedures..... 106 Numerical Experiments to Improve the Fitting Procedure 109 Application o-f Partial Parametric Adjustments. 1 13 Parametric Grouping into Computational Subsets 115 Uniqueness o-f the Solution 121 Smoothing o-f the Observational Data. 122 N-point unweighted smoothing ....123 N-point weighted, exponential smoothing 124 Smoothing by -foward and inverse Fourier trans-f ormt i on 125 IV COMPUTATIONAL DATA REDUCTION PROCEDURES 134 A Choice o-f Programming Languages: The APL Dec i s i on 1 34 Downloading and Uploading of Observational Data '. ~. 136 The Occultation Reduction Workspace <0CCRED> 138 Global Variables Used by OCCRED 139 The Computational Differential Corrections Procedure 141 i x The Two-Star Di f f eren t i al Corrections Procedure (DC2) 154 Global parameters -for DC2 154 The APL function DC2 155 Preprocessing of the Observational Data 158 Presentation o-f the Results o-f the DC Run 158 K> THE OCCULTATION OBSERVATIONS AND RESULTS OF THEIR ANALYSIS 162 Pre sen tat i on Format 162 Format and Content o-f the Tables 162 The occultation summary table.. 162 Uar i ance-covar i ance , correlation, and dl/dPj 167 Observed and computed intensity values 168 Format and Content of the Graphs 169 Graph of the entire event, RAWPLOT 169 The integration plot, INTPLOT 170 Graphic depiction of the best fit, FITPL0T..171 Noise statistics of the observation, NOI SEPLOT 1 72 Power spectra, POWERRPLOT 174 Sensitivity of solution to variation of parameters, PDPLOT 176 Discussion of Individual Occultation Events 177 ZC0916 <1 Geminorum) 177 Historical notes 177 The observat i on .... 1 79 Reduction and analysis of the 1 Geminorum A observation 181 Reduction and analysis of the 1 Gemi norum B observat i on 186 A discussion of the 1 Geminorum results 188 Concluding remarks on 1 Geminorum ...199 ZC1221 (9 Cancri) 204 ZC1222 215 X07589 223 X07598 235 XI 3534 245 XI 3607 256 ZC1 462 265 XI 8067 277 ZC2209 <32 Librae) 285 ZC3214 296 X31 590 307 ZC3458 <334 B.