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1、 AstronomersObserving Guides 01SHO_PRE(i-viii).qxd 3/9/05 12:01 PM Page i Other titles in this series Double and Multiple Stars and How to Observe Them James Mullaney The Moon and How to Observe It Steven R. Coe Related titles Field Guide to the Deep Sky Objects Mike Inglis Deep Sky Observing Steven
2、 R. Coe The Deep-Sky Observers Year Grant Privett and Paul Parsons The Practical Astronomers Deep-Sky Companion Jess K. Gilmour Observing the Caldwell Objects David Ratledge Choosing and Using a Schmitt-Cassegrain Telescope Rod Mollise 01SHO_PRE(i-viii).qxd 3/9/05 12:01 PM Page ii Julius Benton Satu
3、rn and How to Observe It With 96 Figures,86 in Full Color 01SHO_PRE(i-viii).qxd 3/9/05 12:01 PM Page iii Dr.Julius L.Benton,Jr.BS,MS,PhD. Fellow of the Royal Astronomical Society Association Lunar and Planetary Observers (ALPO) Saturn Section Wilmington Island Savannah,6A 31410 USA J Series Editor D
4、r.Mike Inglis BSc,MSc,PhD. Fellow of the Royal Astronomical Society Suffolk County Community College,New York,USA inglismsunysuffolk.edu British Library Cataloguing in Publication Data A catalog record for this book is available from the British Library Library of Congress Control Number: 2005925511
5、 Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright,Designs and Patents Act 1988,this publication may only be reproduced, stored or transmitted,in any form or by any means,with the prior permission in writing of the pub
6、lish- ers,or in the case of reprographic reproduction in accordance with the terms of licences issued by the Copyright Licensing Agency.Enquiries concerning reproduction outside those terms should be sent to the publishers. AstronomersObserving Guides Series ISSN 1611-7360 ISBN-10: 1-85233-887-3e-IS
7、BN 1-84628-045-1 ISBN-13: 978-1-85233-887-3 Springer Science+Business Media Springer-Verlag London Limited 2005 The use of registered names,trademarks,etc.in this publication does not imply,even in the absence of a specifi c statement, that such names are exempt from the relevant laws and regulatio
8、ns and therefore free for general use. The publisher makes no representation,express or implied,with regard to the accuracy of the inform- ation contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. Observing the Sun, along with
9、a few other aspects of astronomy, can be dangerous.Neither the publisher nor the author accept any legal responsibility or liability for personal loss or injury caused,or alleged to have been caused,by any information or recommendation contained in this book. Typeset by EXPO Holdings Sdn Bhd Printed
10、 in Singapore 58/3830-543210Printed on acid-free paper 9 8 7 6 5 4 3 2 1 01SHO_PRE(i-viii).qxd 3/9/05 12:01 PM Page iv This book is dedicated to my father and mother, Julius and Susan Benton, who gave me my fi rst telescope, to my aunt, Mary Ann Jones, who always encouraged my explorations of the he
11、avens,to my family for their patience and understanding as my astronomical endeavors consumed countless hours all these years, to my mentor and longtime friend Walter Haas, and with deepest gratitude to Saturn observers everywhere who faithfully contributed observations to the A.L.P.O. Saturn Sectio
12、n during my tenure as Section Coordinator. 01SHO_PRE(i-viii).qxd 3/9/05 12:01 PM Page v Contents Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. Saturn as a Planet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Telescopes and Acces
13、sories . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 3. Factors that Affect Observations . . . . . . . . . . . . . . . . . . . . . . . . . 75 4. Visual Impressions of Saturns Globe and Ring System . . . . . . . . . . . . 89 5. Drawing Saturns Globe and Rings . . . . . . . . . . . . . .
14、. . . . . . . . . 111 6. Methods of Visual Photometry and Colorimetry . . . . . . . . . . . . . . . 123 7. Determining Latitudes and Timing Central Meridian Transits . . . . . . . 133 8. Observing Saturns Satellites . . . . . . . . . . . . . . . . . . . . . . . . . . 141 9. A Primer on Imaging Satur
15、n and Its Ring System . . . . . . . . . . . . . . 147 Appendix A: Association of Lunar and Planetary Observers (ALPO) Saturn Section Observing Forms . . . . . . . . . . . . . . . . . . 164 Appendix B: Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 Index . . . . . . . . .
16、 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179 Contents vii 01SHO_PRE(i-viii).qxd 3/9/05 12:01 PM Page vii Introduction I received my fi rst telescope, a 60 mm (2.4 in) Unitron refractor, as a surprise Christmas gift from my father when I was 10 years old, and over the next sev
17、eral years, I spent countless hours exploring the heavens, seeking out virtually every celestial object I could fi nd with this small aperture.I consider myself quite fortu- nate to have been blessed with a dark,unobstructed observing site for most of my childhood,unlike many of my astronomical frie
18、nds who were always trying to get to a remote location away from city lights to do worthwhile deep-sky observing.I only had to carry my telescope and star charts just a few feet away into my backyard. By the time I entered high school,the night sky had become a delightfully famil- iar place.I had tr
19、acked down virtually all of the galaxies,nebulae,and star clusters within reach of my little instrument,and I split most of the double stars that were theoretically possible with its exquisite optics.Eventually,I earned suffi cient funds working part-time jobs (and saving school lunch money) to purc
20、hase a premium 10.2 cm (4.0 in) refractor, another Unitron that I quickly put through its paces, once again surveying my favorite deep-sky objects.Despite the fact that I could see all of them much better with increased aperture, I soon recognized how virtually changeless they were, so I started exp
21、anding my observational pursuits. Taking advantage of the increased resolution of the new refractor, my interests evolved almost exclusively to observing the moon and the brighter planets. The wealth of detail I could see on the moon, Jupiter, and Saturn at 250 thoroughly fascinated me,and countless
22、 evenings were occupied watching variations in their appearance. Undeniably,why I ended up being chiefl y a planetary observer had more to do with the continually changing aspect of the moon and planets than anything else.Now that I had substantially improved aperture at my disposal, as well as a gr
23、owing collection of eyepieces and accessories, I naturally wanted to observe the moon and planets more often. I soon realized, however, that one of the drawbacks of a larger instrument is decreased portability. Yet, having to carry my clock-driven telescope from place to place never became much of a
24、n issue,except when I wanted to view comets or asteroids,for experience had taught me that lunar and planetary observing did not necessarily require dark skies or even an absolutely clear horizon.Like I had done so many times in the past,all I needed to do was step right outside my door to observe.A
25、nd so,I routinely followed the moon and most of the brighter planets throughout many wonderful observing seasons. Saturn, though, ultimately became my favorite solar system object, and it was not long before I adopted the practice of making careful drawings and writing down all of my observational n
26、otes in a logbook for future reference. My interest in lunar and planetary astronomy followed me well into my college years.The rather gloomy outlook at the time for potential employment opportuni- ties in astronomy forced me to select a major in physics and the environmental sciences,but I always m
27、ade sure I was never far away from my telescopes on clear Introduction 1 02SHO_INTRO(1-4).qxd 3/9/05 12:01 PM Page 1 nights! By the time I completed my undergraduate studies,my interest in lunar and planetary astronomy had become a virtual obsession, partially ushered in by the unprecedented events
28、of July 20,1969,when Apollo 11 touched down on the moon in the Sea of Tranquility. The following year I attended my fi rst astronomical convention,where for the fi rst time I met Walter Haas,the founder and then exec- utive director of the Association of Lunar and Planetary Observers (ALPO). I discu
29、ssed with him my deep interest in contributing worthwhile lunar and plane- tary observations,and his enthusiasm,encouragement,and guidance helped stim- ulate my involvement in many ALPO activities.For a few more years,however,the rigors of graduate school occupied much of my available time as I purs
30、ued advanced degrees,but I still somehow managed to set aside a few hours a week to spend time at my telescopes recording observations systematically. The congenial, informal atmosphere of the ALPO proved to be refreshing and wonderfully captivating, and I soon developed a real appreciation for the
31、great diversity of backgrounds and experience of the people I met and corresponded with.Sharing many different philosophical and scientifi c viewpoints about instru- mentation and observing proved to be very meaningful over the years.Although I often found serious observing endeavors to be challengi
32、ng work, they were also enormous fun.I enthusiastically welcomed the opportunity to contribute all of my own observations to a collective pool of data that had the potential for enhancing our knowledge about Saturn and the solar system as a whole. Through an active exchange of information and ideas
33、in a collective forum, many individuals improved as observers,including myself,and some even went on to become profes- sional astronomers. In addition, I had not been a member of the ALPO for very long before I discovered that the The Strolling Astronomer (also known as the Journal of the Associatio
34、n of Lunar and Planetary Observers) was essential reading. Most of the information contained within its pages seldom existed elsewhere,and this publication for many years has helped establish and preserve a vital link between the amateur and professional astronomical communities that might not other
35、wise exist. Annual conventions, often held jointly with other national and international groups, were always enjoyable events as much as they proved to be intellectually stimulating. I can attribute many lasting friendships to such meetings. In 1971 I was appointed coordinator of the ALPO Saturn Sec
36、tion. I was truly honored to be selected to serve in such a role, and I valued the confi dence placed in me by my mentor,Walter Haas,and other ALPO colleagues.Any small contribu- tion that I have been able to make to what we know about the planet Saturn from the standpoint of observational astronomy
37、 has come as a sincere labor of love, something I have never grown tired of even after nearly 34 years of recording, analyzing, and publishing detailed apparition reports. But whatever success the ALPO Saturn Section has achieved, none of it would have been possible without the enthusiasm and persev
38、erance of many dedicated observers too numerous to mention here. Like many of my contemporaries,I consider myself very fortunate to have grown up during the Space Age, witnessing fi rsthand the enormous revelations and progress made in planetary science.It has been fascinating to watch the marvelous
39、 transformation of our nearest celestial neighbors from virtually unknown and inaccessible objects into much more familiar worlds over little more than three decades. With such rapidly occurring advances, I suppose it may be tempting to conclude that the work of amateur astronomers long ago passed i
40、nto obsolescence Introoduction 2 02SHO_INTRO(1-4).qxd 3/9/05 12:01 PM Page 2 from our fi xed and limited vantage point in space.And,yes,it is obvious that lunar explorations by the Apollo astronauts or the close surveillance of planets and satel- lites by orbiting,impacting,or roving spacecraft are
41、clearly beyond the domain of the Earth-based amateur astronomer.But make no mistake about it: there are still many areas of lunar and planetary observation where the work of amateur astronomers has not been outmoded by the onslaught of prohibitively expensive and imposing equipment.Unlike many of th
42、eir professional counterparts,amateur astronomers continue to enjoy the virtual freedom and advantage of being able to study their favorite solar system objects for extended periods of time and precise- ly when they want to. Indeed, the greatest potential visual observers have for making useful cont
43、ributions to science is a systematic, long-term, and simultane- ous monitoring of the moon and planets at wavelengths of light to which the eye has greatest sensitivity. An enduring advantage that trained eyes of skilled amateurs have is the unique ability to perceive,at intermittent moments of exce
44、p- tional seeing,subtle detail on the surfaces and in the atmospheres of solar system bodies that frequently escapes normal photography with considerably larger aper- tures.And while being careful not to abandon fundamentally important systemat- ic visual work, more and more observers are employing
45、sophisticated electronic devices such as charged couple devices (CCDs), specialized video cameras, and webcams to record impressive, detailed images of the planet, far surpassing what had been previously possible by astrophotography. Furthermore, well-organized systematic work by dedicated amateurs
46、has increasingly caught the attention of the professional community, evidenced by several invitations extended to them for participation in specialized research projects. Simultaneous observing programs and close professionalamateur alliances have already carried over into the 21st century and will
47、undoubtedly grow in the coming years. If we considered the planet only as a globe,Saturn would be a somewhat smaller, dimmer, and relatively quiescent replica of the giant Jupiter. But, with its broad symmetrical rings, Saturn is an object of exquisite and unsurpassed beauty, holding a particular ma
48、gnetism for the visual and photographic observer alike. Aside from its obvious aesthetic qualities, the planet exhibits numerous features requiring persistent and meticulous observation, plus eight satellites that are readily accessible to moderate-size telescopes if observers know where to look. In
49、 this book,the reader will learn about how to observe Saturn,its rings,and brighter moons using methods, techniques, instruments, and accessories that are readily available to amateur astronomers. One of the major objectives I hope to accom- plish is to fi rst acquaint the reader with some fundamental,up-to-date information about Saturn as a planet,then focus on the basics involved in recording useful data and reporting observational results,plus offer suggestions for more advanced and specialized work.Observers will discover how they can take part i
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