Gary W. Kronk Meteor Showers An Annotated Catalog Second Edition The Patrick Moore The Patrick Moore Practical Astronomy Series For further volumes: http://www.springer.com/series/3192 Meteor Showers An Annotated Catalog Gary W. Kronk Second Edition Gary W. Kronk Hillsboro , MO , USA ISSN 1431-9756 ISBN 978-1-4614-7896-6 ISBN 978-1-4614-7897-3 (eBook) DOI 10.1007/978-1-4614-7897-3 Springer New York Heidelberg Dordrecht London Library of Congress Control Number: 2013948919 © Springer Science+Business Media New York 1988, 2014 This work is subject to copyright. All rights are reserved by the Publisher, whether the whole or part of the material is concerned, speci fi cally the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on micro fi lms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilar methodology now known or hereafter developed. Exempted from this legal reservation are brief excerpts in connection with reviews or scholarly analysis or material supplied speci fi cally for the purpose of being entered and executed on a computer system, for exclusive use by the purchaser of the work. Duplication of this publication or parts thereof is permitted only under the provisions of the Copyright Law of the Publisher’s location, in its current version, and permission for use must always be obtained from Springer. Permissions for use may be obtained through RightsLink at the Copyright Clearance Center. Violations are liable to prosecution under the respective Copyright Law. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publication does not imply, even in the absence of a speci fi c statement, that such names are exempt from the relevant protective laws and regulations and therefore free for general use. While the advice and information in this book are believed to be true and accurate at the date of publication, neither the authors nor the editors nor the publisher can accept any legal responsibility for any errors or omissions that may be made. The publisher makes no warranty, express or implied, with respect to the material contained herein. Printed on acid-free paper Springer is part of Springer Science+Business Media (www.springer.com) This book is dedicated to my wife and best friend, Kathy. About the Author Gary W. Kronk received his Bachelor of Science in Journalism from Southern Illinois University in Edwardsville. He is employed at Laclede Gas in St. Louis, where he is a Senior User Support Specialist and occasionally teaches classes on software programs. Observing, researching, and writing about comets has been an activity the author has participated in for most of his life, with over 3,000 observations of over 210 comets. He is the author of seven books and has published in Sky & Telescope , Astronomy , Icarus , The Journal of the Association of Lunar and Planetary Observers , and more. His books include Comets: A Descriptive Catalog (Enslow Publishers, 1984), Meteor Showers (Enslow, 1988), and a six-volume series titled “Cometography” with Cambridge University Press, whose fi fth volume was pub- lished in 2010. In 2004, the International Astronomical Union’s Minor Planet Center announced that minor planet number 48300 was being given the name “Kronk” in honor of the author’s extensive research for his Cometography series. vii Preface This book contains both historical and current data on what the author believes to be the most active meteor showers in the sky. Data from the majority of the visual, photographic, video, and radar studies have been utilized. The author began his research in the late 1970s with in-depth investigations into the observations of several major meteor showers, such as the Perseids, Geminids, Orionids, and Eta Aquarids. This ultimately took the author in a new direction that led to the creation of a preliminary list of over 600 potential meteor showers. Using photographic and radar data, the author determined the orbit of each potential meteor stream. When such data was not available, the author calculated parabolic orbits for the streams. The next stage was to establish the probable daily movement of each meteor stream’s radiant across the sky (also known as the radiant ephemeris). Dozens of radiant lists published during the nineteenth and twentieth centuries, as well as lists of photographic and radar meteor orbits were then compared to each preliminary radiant ephemeris of each potential meteor shower. Finally, the “D-criterion” was applied to the potential matches, which ultimately determined the history of each stream, the actual duration, the actual radiant ephemeris, and the orbit. This analysis fi rst began on a CDC Cyber 90 mainframe at Southern Illinois University in Edwardsville (Illinois, USA) in 1980. Work continued on an Atari 800 home computer (48 K RAM) in 1982 and a Macintosh (512 K and 1 M RAM) from 1985 to 1987. To update the fi rst edition of this book, some of this same analy- sis was repeated during the last 2 years using an Apple iMac computer with an 8 GB RAM running both Apple OS X and Microsoft Windows 7. ix x Preface The meteor showers chosen to be included in this book are here for one or more of the following four reasons: 1. They are among the strongest showers. 2. They have been known for a long time. 3. They have had support from at least two very reliable and methodical surveys. 4. They are particularly interesting. Obviously, the fi nal decision on what stayed and what was taken out was purely the decision of the author and, admittedly, some weak meteor showers that met some of these criteria were left out because of lack of space. This book is divided into 12 chapters, with each chapter covering a month of the year. Meteor showers are included in the month that they reach maximum and are listed alphabetically according to their constellation name. For each meteor shower, the author has presented what may be the fi rst observations, additional observa- tions, and the orbit. For well-observed meteor showers, the author has also included the duration of activity, date of peak activity, average radiant position, and many additional details. There are a couple of showers that have a maximum which can fall on either the last day of one month or the fi rst day of the next month (the Delta Aquariids are one example), but the author has dealt with this by placing the shower in the chapter containing the earliest date of maximum. For the fi rst edition of this book, the author adopted either the most commonly used name or, on occasion, the most appropriate name for each shower. Since the writing of that edition, the International Astronomical Union has adopted new names for some meteor showers. Subsequently, some meteor showers in the fi rst edition have been renamed in this edition. Although the month, day, and year are given in the discussion of every meteor shower, the actual time is rarely given, except in the case of unusual events, such as outbursts of meteors. When the time is provided, it is handled in one of two ways throughout this book: local time or universal time. Both of these times are mostly used in the case of outbursts. The local time is usually only used during the eighteenth, nineteenth, and early twentieth centuries. It is the time the observer records by looking at a timepiece of some type. Outbursts are usually events of very short duration, so the author chose to just use the local time to give the reader a better sense of the situation. For example, the discussion of the 1833 outburst of the Leonids mostly discusses the observations along the east coast of the United States, because this is where the bulk of the observations were made at the peak. Throughout the text, the local time is identi fi ed as times that are followed by “a.m.” or “p.m.” Universal time was adopted by the International Astronomical Union in 1935 and became the standard for astronomical observations. It is the result of taking the local time and adding or subtracting the number of hours between the time zone of the observer and the Greenwich meridian. Observations in universal time are listed in two different ways throughout the book, depending on the situation. If you read that an observer saw 30 meteors on “2005 August 12 from 20:05 to 21:05,” this is Preface xi simply indicating the hour and minutes in universal time (always in the 24-h for- mat) that 30 meteors were seen. If you read a date such as “1999 November 18.01,” this is the result of the hours and minutes in universal time being divided by 24 h to get the decimal day. These two methods of displaying universal time exist in this book because that is the way they were reported. Another important piece of information when dealing with observations is the number of meteors seen. The most common way to express this number is “meteors per hour,” also called the “hourly rate.” These two phrases are used throughout the book and provide the reader with a sense of what was actually seen. For analysis purposes, astronomers use a formula to convert the hourly rate to the “zenithal hourly rate,” which is abbreviated as ZHR. This value allows astrono- mers to compare the observations from a wide variety of people, as the formula considers the sky conditions at each location, the altitude of the radiant at the time of the observation, the amount of unobstructed sky (i.e., free of trees and buildings), observer perception, and other factors.