Excursions in Astronomical Optics

156 Pages·1996·3.805 MB·English

by  Lawrence Mertz (auth.)

Excursions in Astronomical Optics ______
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Lawrence Mertz __________
Excursions in
Astronomical Optics
With 107 Illustrations
, Springer
Lawrence Mertz
287 Fairfield Court
Palo Alto, CA 94306
USA
Library of Congress-in-Publication Data
Mertz, Lawrence.
Excursions in astronomical optics 1 Lawrence N. Mertz.
p. cm.
Includes bibliographical references and index.
ISBN-13: 978-1-4612-7522-0 e-ISBN-13: 978-1-4612-2386-3
DOl: 10.1007/978-1-4612-2386-3
1. Astronomical instruments. 2. Optics. 3. Telescopes.
4. Interferometry. I. Title.
QB86.M47 1996
522' .2--{)c20 95-51497
Printed on acid-free paper.
© 1996 Springer-Verlag New York, Inc.
Softcover reprint of the hardcover 1s t edition 1996
All rights reserved. This work may not be translated or copied in whole or in part without the written
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Production managed by Frank Ganz; manufacturing supervised by Joe Quatela.
Camera-ready copy prepared from the author's TEX files.
987654321
SPIN 10526943
In memory of my son,
Thomas Mertz
1965-1980
Preface
For every astronomical topic that I have approached there has turned out to be
a broader realm of possibilities than is commonly accepted or acknowledged.
The "excursions" of this book are the examples. They mostly depart from the
mainstream of conventional wisdom to offer a wider perspective with opportunities
for further research. While my intent is to supplement that mainstream, the effect
may appear to dismiss rather than to reconsider accepted tenets. Ample praise and
credit for those accomplishments are already available in textbooks. Readers may
very well disagree with some of the notions presented in these excursions, but
I hope that they will pause long enough to evaluate the scientific basis for any
disagreement.
For the most part, these excursions remain incomplete and unfulfilled, yet they
contain many ideas that are not available elsewhere. Whether these ideas are per
ceived as a collection of unproven claims or as a storehouse of fresh opportunities
will depend entirely on the attitude of the reader.
The excursions do cover a rather wide span of disciplines, and that may lead to
an unfocused overall impression. My hope is thereby to attract a broader audience
than that of a single discipline, and to expose them to neighboring disciplines. The
excursions all do have the common thread of optical science related to astronomy.
The intended audience is workers at the graduate, engineering, or research level
engaged in one or more of the various fields. What I have tried to do in each case is
to provide the reader with sufficient information to accomplish the unusual projects
that are described. For example, the programs given in the Appendices will let the
reader make for himself the content of illustrations found in the first two chapters,
and then to make his own variations.
Chapter 4 is admittedly rather bland in that the directions have been largely
overtaken by more recent advances in image processing, adaptive optics, and laser
guide stars. The only reason for retaining it is that there still may be a few items
of interest.
Chapters 6 and 7 may seem incongruous with the other excursions, intruding
on theoretical turf. They are simply interpretations of the observations from the
perspective of an experimentalist in optical science. That extra perspective offers
viii Preface
fresh alternatives where theorists may have been too quick in jumping to conclu
sions with their explanations of pulsars and quasars. At any rate, I hope that these
chapters give some grist for thought.
This book is a sequel to my prior book, Transformations in Optics [Wiley,
1965], and chronicles my research activities since then. Those activities delimit
the scope of the topics. They have been fascinating and stimulating for me. Some
of the references mentioned in the Bibliographies are not explicit in the text, but
they nevertheless played a role in influencing the text. Also, the Bibliographies
are not as thorough nor as up to date as they ought to be because my access
to libraries is no longer as convenient as it used to be. As with most authors,
there is excess reference to my own contributions simply because of familiarity.
I have benefited from conversations with many friends and colleagues over these
years. The most longstanding have concerned interferometry with Gerry Wyntjes,
formerly of Block Associates and then of Optra. I am grateful to him and to the
many others who have encouraged and influenced this work.
August 1994 L.Mertz
Contents
Preface vii
1. Optical Telescopes 1
Introduction
Modest Telescopes . 2
Large Telescopes 4
Fixed Spherical Primary 6
Optical Design 11
Dihedral Remedy 16
Microscope Objectives 18
Telescope Correction . 19
Alternative Prescriptions 22
Geometric Variants . 23
Bibliography 24
2. X-ray Telescopes 25
Introduction 25
Coded Aperture Imaging 25
Moire Telescopes 28
Rotation Modulation Collimator 30
Rotational Aperture Synthesis 37
Monte Carlo Simulation . 39
Upscale Rendering . 42
Bibliography 44
3. Interferometry 47
Introduction 47
Triphase Reception 49
Unwrapping and Filtering 52
Substantial Intensities 56
x Contents
Flash Conversion 57
Angle Encoder . 60
Oversampling. . 63
Second-oder Filtering . 66
Analog Comparison . 67
Stellar Interferometry . 69
More Applications . . 70
Quantum Ramifications 73
Bibliography . 76
4. Image Sensing 79
Imaging Photon Counters 79
Heterodyne Detectors . 81
Fourier Tracking 82
Image Stabilization 85
Wavefront Tilt Sensors 86
Interferometric Wavefront Sensing 87
Prismatic Wavefront Tilt Sensor 89
Holographic Wavefront Tilt Sensor 89
Wavefront Curvature Sensing 90
Prismatic Variants 92
Bibliography . . . . . . . 94
5. Spectroscopy •• 95
Following Dyson 95
Following Offner 99
Whispering Galleries 100
Fourier Transform Spectroscopy 102
Nonlinear Analyses 105
Bibliography . . . . . . . . 107
6. Pulsars ••. 109
Introduction 109
Cavity Clocking 109
Degenerate Dwarfs . 110
Period Distribution . 112
Period-luminosity Cutoff 114
Short Periods . . . 115
Slowdowns .... 116
Energy and Pumping 117
Pulse Formation 118
Mode-hopping 119
Polarization 120
Contents xi
Visible and X-ray Pulses 121
Jovian Decametric Emission 122
Summary 123
Bibliography 123
7. Quasars . . 127
Introduction 127
Superluminal Illusion . 128
Gravitational Lensing . 129
Experimental Simulation 131
Brightness Fluctuations . 132
Distance Scale Corruption 133
Foreground Localization 133
Gravitational Amplification 135
Bibliography 137
Appendix 1 . 139
Appendix 2 . 145
Index . . . 151