***** File PREFACE.TXT PREFACE The International Halley Watch (IHW) grew out of a National Aeronautics and Space Administration (NASA) sponsored study in 1979-80 led by Louis Friedman of the Jet Propulsion Laboratory (JPL). The premise behind that study was that some form of cooperation among the astronomers and space scientists of the world would be necessary to make the most of the once per lifetime opportunity to study Comet Halley. It was obvious that international cooperation required sponsorship by the International Astronomical Union (IAU), and that had to be obtained at the 1982 General Assembly of the IAU or preparations could not be ready in time for Halley. This set the timing for creation of the entire IHW organization. In 1980 NASA organized a Lead Center for the western hemisphere at JPL under Ray Newburn. A similar facility for the eastern hemisphere was organized at Dr. Remeis Sternwarte, Bamberg, under Juergen Rahe with the support of the government of the Federal Republic of Germany. Newburn and Rahe elaborated upon the plans of the original study group, which suggested appointment of specialists to set up networks of observers in each of the major observing disciplines, establishment of an international oversight committee, coordination with the planned space projects, and cooperation with amateur observers. In 1981 a Steering Group of 22 scientists residing in 12 different countries was appointed by NASA to help establish the other parts of the IHW and to advise on its operation. Later this international group became independent of NASA, elected its own chairman, and added and/or replaced members as it felt necessary. The Steering Group selected Discipline Specialists based on formal proposals submitted in response to a NASA letter, mailed worldwide, seeking cometary scientists to organize the observing networks, coordinate their activity, and later to assist in archiving the resulting data. By the time of the 1982 IAU meeting a complete administrative organization was in existence, awaiting its acceptance and imprimatur by that worldwide group. The original study at JPL suggested that the most important product of the IHW should be an archive of all the data. The archive was not to replace the normal interpretation and publication in technical journals. Rather it was to complement those publications by establishing a comprehensive database suitable for further studies requiring reduced but uninterpreted data from many observers and different disciplines. The complete archive would be given to each observer contributing to it and made available to institutes worldwide. Cost of this publication would be borne by NASA. Initially this was envisioned as a printed archive. Almost immediately it became obvious that to maintain full quantitative accuracy a digital version of the archive would be necessary. The logic leading to the selection of CD-ROMs as the digital medium is presented in another file. In 1981 Newburn and Rahe presented the IHW idea to the first joint meeting of the space agencies planning to send probes to Halley. That meeting led to a permanent organization known as the Interagency Consultative Group (IACG). The IACG was especially interested in the proposed Astrometry Network of the IHW as a possible source of data for their spacecraft navigation, and the IHW continued to be represented at IACG meetings as long as their primary agenda item was Halley. When NASA decided to shift its ISEE (International Sun-Earth Explorer) spacecraft into a trajectory encountering Comet Giacobini-Zinner (G-Z), it was natural to request that observations of G-Z be coordinated by the IHW as well, and this was done. In publishing the archive there seemed to be no good reason to mix G-Z data with those of Halley. Further, with the G-Z observations completed much earlier than those of Halley, publication of a separate "G-Z Archive" would offer a chance to make a final test of the end-to-end data handling capabilities of the IHW. All IHW software necessary for Halley therefore was utilized to produce a test CD of the G-Z data. That test disc was used by 100 different scientists in the same way as the final Halley archive is intended to be used and tested for readability and accessibility. The "real" and final G-Z archive disc distributed here together with the Halley discs is thus the product of a long developmental process which we hope has led to a package of use to many scientists. At this writing the decision has been made to prepare camera ready copy for a printed version of the archive, while personnel and facilities are still available for the job. A printed archive would be useful to many people, and an archive printed on acid-free paper would have true archival durability. The durability of CDs is unknown, and even if they survive without problems until the next apparition of Halley, CDs may be as obsolete as Edison cylindrical phonograph records by 2061. The actual printing of the archive awaits availability of funds, however, which makes printing before FY 1992 unlikely. Ray L. Newburn, Jr. Jrgen Rahe Leaders, International Halley Watch November, 1990