***** File INTRODUC.TXT INTRODUCTION The Archive of Periodic Comet Giacobini-Zinner has been completed in two versions, the digital and the printed, regardless of whether or not the latter will be distributed. The comet's reduced observations belong to one of the following disciplines or networks: 1. Astrometry. 2. Infrared Studies. 3. Large-Scale Phenomena. 4. Near Nucleus Studies. 5. Photometry and Polarimetry. 6. Radio Studies. 7. Spectroscopy and Spectrophotometry. 8. Amateur Observations. The P/Giacobini-Zinner campaign has not involved the Meteor Streams Studies Network. The Infrared Studies Network, the Photometry and Polarimetry Network, the Radio Studies Network, and the Amateur Observations Network are organized into the following subnetworks: Infrared Studies Subnetworks: 2.1. Infrared Photometry. 2.2. Infrared Polarimetry. 2.3. Infrared Spectroscopy. 2.4. Infrared Imaging. Photometry and Polarimetry Subnetworks: 5.1. Broadband Photometry. 5.2. Narrowband Photometry. 5.3. Polarimetry. Radio Studies Subnetworks: 6.1. Hydroxyl Feature at 18 cm. 6.2. Spectral Line. 6.3. Continuum. 6.4. Occultation. Amateur Observations Subnetworks: 8.1. Visual-Appearance Descriptions. 8.2. Drawings. 8.3. Photographs. The digital version of the Archive, stored on a CD-ROM, includes a number of subdirectories, each of which contains one or more files with relevant explanations. One of the subdirectories, called EPHEM, provides the comet's geocentric ephemeris (equinox and mean equator 1950.0) for midnight Universal Time of each day, covering the interval of observations. In the printed version of the Archive the reduced observations are integrated chronologically by date and by network for each date. The ephemeris is in this version listed with the observations for each date, preceding the data of the first network that was active. The digital Archive is written in the Flexible Image Transport System (FITS) format (Wells, Greisen, and Harten, Astron. Astrophys. Suppl. Ser. 44, 363-370, 1981; Greisen and Harten, Astron. Astrophys. Suppl. Ser. 44, 371-374, 1981; Grosbol, Harten, Greisen, and Wells, Astron. Astrophys. Suppl. Ser. 73, 359-364, 1988; Harten, Grosbol, Greisen, and Wells, Astron. Astrophys. Suppl. Ser. 73, 365-372, 1988). The data appear either as part of FITS headers or in FITS data records or in table extensions. The FITS headers consist of keywords, some of which are mandatory (dictated by use of the FITS format or stipulated by IHW), while others were selected, as needed, by the Discipline Specialist Team and apply only to specific networks. With the exception of the digitized images supplied by the Large-Scale Phenomena Network, the data are combined into a number of subdirectories. The large-scale images appear both uncompressed and compressed and they are included in separate subdirectories. The digital Archive is also accompanied by three types of indices: quick-look, printed- archive, and network-specific (see subdirectories DOCUMENT and INDEX for additional information). The evaluation of submitted observations and their selection for the Archive has primarily been the responsibility of the Discipline Specialist Teams in charge of the networks. To expound the process of evaluation, reduction, and formatting of the database, each Discipline Specialist Team has provided network by network, an outline and a data-organization description of both the digital and the printed versions of the Archive. This documentation follows the Introduction. It is supplied to facilitate the user's orientation in the Archive and to furnish information on the reduction procedures employed to obtain the archived results from the measured data. Table I of each network's section lists the names, affiliations, and responsibilities of the members of the Discipline Specialist Team. Appended to the descriptive section of the Archive is a table of the observatories and instruments, the 8-digit system codes, and the geographic coordinates; and a table of country codes. The observatories with and without the IAU assigned codes are listed separately. The countries are tabulated both alphabetically and by code. In addition, the printed version of the Archive displays histograms of the distributions of each network's observations. This Archive is a result of major efforts on the part of a large number of individuals, from the observers to the Discipline Specialist Teams to the personnel of the two Lead Centers. The user has in his hands information that in the absence of this Archive would either remain unpublished or would have to be acquired through a time-consuming search in the literature. We therefore consider it fair to request the users that this document be acknowledged in the references of any of their publications that employ the data presented here. Zdenek Sekanina Editor Jet Propulsion Laboratory California Institute of Technology 4800 Oak Grove Drive Pasadena, California 91109 U.S.A. Pasadena, March 1989