NASA RP 1383: Preface (original) (raw)

This is the fifth in a series of NASA Eclipse Bulletins containing detailed predictions, maps and meteorological data for future central solar eclipses of interest. Published as part of NASA's Reference Publication (RP) series, the bulletins are prepared in cooperation with the Working Group on Eclipses of the International Astronomical Union and are provided as a public service to both the professional and lay communities, including educators and the media. In order to allow a reasonable lead time for planning purposes, subsequent bulletins will be published 24 to 36 months before each event.

Single copies of the bulletins are available at no cost and may be ordered by sending a 9 x 12 inch SASE (self addressed stamped envelope) with sufficient postage (11 oz. or 310 g.). Use stamps only; cash or checks cannot be accepted. Requests within the U. S. may use the Postal Service's Priority Mail for $3.00. Please print either the eclipse date (year & month) or the NASA RP number in the lower left corner of the SASE. Requests from outside the U. S. and Canada may send nine international postal coupons to cover postage. Exceptions to the postage requirements will be made to professional researchers and scientists, or for international requests where political or economic restraints prevent the transfer of funds to other countries. All requests should be accompanied by a copy of the request form on page 97.

A significant change in the 1998 bulletin is the use of a far more detailed mapping data base for the path figures. World Vector Shoreline (WVS) and World Data Bank II (WDBII), were developed by the Defense Mapping Agency (U. S. Department of Defense), and the U. S. Central Intelligence Agency, respectively. The WDBII outline files were digitized from navigational charts to a working scale of approximately 1:3,000,000, and represent the "state of the art" in the mid 1970s. The WVS data sets are given at several resolutions, including 1:1,000,000, 1:250,000, and 1:100,000. For maximum efficiency and speed, these data have been compressed and reformatted into direct access files by Jan C. Depner (U. S. Naval Oceanographic Office) and James A. Hammak (NORDA). WDBII and WVS are available through the "Global Relief Data CD-ROM" from the National Geophysical Data Center. These vector data have made it possible to generate eclipse path figures at resolutions greater that 1:10,000,000. This has been particularly useful in generating detailed figures of the eclipse path through individual islands in the Caribbean. We've also enhanced these figures by adding curves of constant duration of totality within the umbral path. This permits the user to quickly estimate the duration of totality at various locations shown in the figures.

We have also implemented a major update in our geographic coordinates data base of cities which has grown from around 4,000 locations to over 90,000. This permits the identification of many more cities within the umbral path and their subsequent inclusion in the local circumstances tables. These same coordinates are plotted in the path figures and are labeled when the scale allows. The source of these coordinates is Rand McNally's The New International Atlas. A subset of these data has recently become available for us in a digital form which we've augmented with population data from the same source. Such modifications and enhancements to software and data bases can be quite time consuming and have inadvertently delayed the publication of the 1998 bulletin by several months. We hope our readers will forgive the delay since we believe these changes have significantly enhanced the coverage and level of detail demanded by this eclipse. Furthermore, future eclipse bulletins will also profit from these changes. Our long term goal is to eventually make the bulletins available a minimum of 3 years in advance.

The bulletins have undergone a great deal of change since their inception in 1993. Some of these changes are the direct result of suggestions from our readers. We strongly encourage you to share your comments, suggestions, and criticisms on how to improve the content and layout in subsequent editions. Although every effort is made to ensure that the bulletins are as accurate as possible, an error occasional slips by. We would appreciate your assistance in reporting all errors regardless of their magnitude.

Thanks to Dr. Joe Gurman (GSFC/Solar Physics Branch), the four most recent eclipse bulletins are available over the Internet. They can be read or downloaded via the World-Wide Web server with a Mosaic or Netscape client from Goddard's Solar Data Analysis Center (SDAC) home page: http://umbra.nascom.nasa.gov/sdac.html. Most of the files are also available via anonymous ftp. Umbral path data for all central eclipses through the year 2005 are also available. Complete details may be found on pages 22 through 24. Naturally, all future eclipse bulletins will also be available via Internet. Since the eclipse bulletins are of a limited and finite size, they cannot include everything needed by every scientific investigation. Some investigators may require exact contact times which include lunar limb effects or for a specific observing site not listed in the bulletin. Other investigations may need customized predictions for an aerial rendezvous or from the path limits for grazing eclipse experiments. We would like to assist such investigations by offering to calculate additional predictions for any professionals or large groups of amateurs. Please contact Espenak with complete details and eclipse prediction requirements.

We would like to acknowledge the valued contributions of a number of individuals who were essential to the success of this publication. The format and content of the NASA eclipse bulletins has drawn heavily upon over 40 years of eclipse Circulars published by the U. S. Naval Observatory. We owe a debt of gratitude to past and present staff of that institution who have performed this service for so many years. The many publications and algorithms of Dr. Jean Meeus have served to inspire a life-long interest in eclipse prediction. We thank Francis Reddy, who helped develop the data base of geographic coordinates for major cities used in the local circumstances predictions. This geographic data base has recently been expanded to include approximately 90,000 cities thanks to the kind assistance of Rique Pottenger of Astro Communications Service. Eric Hui was instrumental in making the WDBII and WVS data bases accessible to our eclipse software by translating a PC "C" program into Macintosh "pascal". Dr. Wayne Warren graciously provided a draft copy of the IOTA Observer's Manual for use in describing contact timings near the path limits. Dr. David W. Dunham offered invaluable assistance in developing the tables of "Mapping Coordinates for the Zones of Grazing Eclipse."

The assistance of Selvin Burton of the Caribbean Meteorological Institute in Barbados, Ambassador F�lix Rossi Guerrero of the Venezuelan Embassy in Canada, Jose Daniel Pabon C., Subdirector de Meteorologia, Instituto de Hidrologia, Meteorologia, y Estudios Ambientales, Colombia and W. K. S. C. Ramsoekh of the Royal Netherlands Embassy in Ottawa is acknowledged. Their help in providing weather statistics has considerably improved this work.

Dr. Jay M. Pasachoff kindly reviewed the manuscript and offered a number of helpful suggestions. The availability of the eclipse bulletins via the Internet is due to the efforts of Dr. Joseph B. Gurman. The support of Environment Canada is acknowledged in the acquisition and arrangement of the weather data. Finally, the authors thank Goddard's Laboratory for Extraterrestrial Physics for several minutes of CPU time on the LEPVOY computer. The time was used for verifying predictions generated with the Macintosh.

Permission is freely granted to reproduce any portion of this Reference Publication, including data, figures, maps, tables and text. All uses and/or publication of this material should be accompanied by an appropriate acknowledgment (e.g. - "Reprinted from Total Solar Eclipse of 1998 February 26 Espenak and Anderson, 1996"). We would appreciate receiving a copy of any publications where this material appears.

The names and spellings of countries, cities and other geopolitical regions are not authoritative, nor do they imply any official recognition in status. Corrections to names, geographic coordinates and elevations are actively solicited in order to update the data base for future eclipses. All calculations, diagrams and opinions are those of the authors and they assume full responsibility for their accuracy.

Fred Espenak Jay Anderson NASA/Goddard Space Flight Center Environment Canada Planetary Systems Branch, Code 693 900-266 Graham Avenue Greenbelt, MD 20771 Winnipeg, MB, USA CANADA R3C 3V4 Fax: (301) 286-0212 Fax: (204) 983-0109 E-mail: espenak@lepvax.gsfc.nasa.gov E-mail: jander@cc.umanitoba.ca

Current and Future NASA Solar Eclipse Bulletins:

NASA Eclipse Bulletin RP # Publication Date

Annular Solar Eclipse of 1994 May 10 1301 April 1993 Total Solar Eclipse of 1994 November 3 1318 October 1993 Total Solar Eclipse of 1995 October 24 1344 July 1994 Total Solar Eclipse of 1997 March 9 1369 July 1995 Total Solar Eclipse of 1998 February 26 1383 April 1996 Total Solar Eclipse of 1999 August 11 1398 March 1997

Total Solar Eclipse of 2001 June 21 ---- Summer 1997 Total Solar Eclipse of 2002 December 4 ---- Summer 1998

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