Addition of spacecraft data to the IHW comet Halley CD-ROM archive

The digital archive of the International Halley Watch is a collection of 26 CD-ROMs containing the data submitted by more than 1500 scientists involved in the measurement of comet 1P/Halley during its last apparition. The collection includes the remote observations (mostly ground-based but with some Earth-orbital observations as well) and the measurements made in situ by the spacecraft that encountered comets 1P/Halley (March 1986) and 21P/Giacobini-Zinner (Sept. 1985). In addition, one volume contains data on comet 27P/Crommelin. Volumes 1–24 have been described previously by Grayzeck et al. (Planet. Space Sci. 43, 225–238, 1995). This article details the spacecraft measurements of comets 1P/Halley and 21P/Giacobini-Zinner contained on the final two volumes (25 and 26) of the IHW CD-ROM series. Most of these data were initially collected by the IHW but, as it passed out of existence, the final task of completing the volumes has been the work of the Small Bodies Node (SBN) of the Planetary Data System (PDS).