The landmark CfA Redshift Survey of galaxy distribution 

 was exrended to the sky above the Southern Hemisphere. 

 Done in collaboration with four other observatories, this map- 

 ping brings the total of galaxies surveyed to more than 14000 

 and represents coverage of about one-third of the sky. The 

 striking bubble-like patterns of large-scale structure seen ear- 

 lier in the northern survey continue in the south. Indeed, anal- 

 ysis of galaxy distribution continues to show evidence for 

 clustering on very large scales, inconsistent with the predic- 

 tions of many cosmological simulations. The CfA survey, com- 

 bined with the Southern Sky Survey, forms the largest and 

 broadest extant galaxy map. 



To hasten the completion of Redshift Survey, a new spectro- 

 graph was installed on the FLWO 1.5-meter-diameter tele- 

 scope, which remains dedicated to the task of measuring 

 galactic redshifts. The new CCD-based (electronic detector) 

 instrument is 5 to 10 times more efficient than the old "Z- 

 machine" used for the initial survey. 



Another new instrument, the Solid State Photomukiplier, 

 was used to make ultra-high time-resolution measurements of 

 the Crab pulsar. These measurements, in contrast to older, less 

 accurate observations, confirmed the outer magnetospheric 

 gap model of pulsar high-energy emission. 



Proiect IOTA, a two-element optical and infrared interfer- 

 ometer intended for high-resolution observations of astronomi- 

 cal objects, installed at the Whipple Observatory, took its 

 "first light," i.e., the infrared measurement of a single star by 

 the system's two separated telescopes, in early December 1993. 



The ninth successful flight of the balloon-borne Far- 

 Infrared Spectrograph (FIRS) set a new upper limit on strato- 

 spheric HBr as well as confirming basic stratospheric 

 chemistry models with additional measurements of HOC1, 

 OH and H ; 0, which accurately predict the CIO abundance, a 

 key molecule in the catalytic destruction of ozone. 



Significant progress continued to be made on the conver- 

 sion ot the Multiple Mirror Telescope to use a single 6.5-m 

 spin-cast borosilicate mirror. For example, the mirror blank's 

 backside was ground flat in preparation for grinding and pol- 

 ishing the parabolic front surface. "First light" is still pro- 

 jected for early 1997- 



Planetary Sciences Division 

 Brian Marsden, Associate Director 



Research in Planetary Sciences is carried out along observational, 

 laboratory, computation, and theoretical lines by scientists with 

 training either in geology or in astronomy/astrophysics. Tradi- 

 tionally, this Division has been concerned with the small bodies 

 of the solar system, including meteors, with particular interest in 

 the positional observation and orbital determination of comets 

 and minor planets. The Division also serves as headquarters for 

 the International Astronomical Union's Minor Planet Center and 

 Central Bureau for Astronomical Telegrams. 



Specific projects include study of the long-term effects of 

 Jupiter and Saturn on the population of the outer part of the 



asteroid belt. An extensive observational program using mod- 

 ern electronic devices on large telescopes is obtaining spectra 

 of faint solar-system objects, notably of cometary nuclei, Tro- 

 jan asteroids, and Jupiter's outer satellites. Another effort 

 seeks to increase significantly the rate of discovery and appro- 

 priate followup of near-Earth asteroids (or comets). Geological 

 research mainly involves the petrology of extraterrestrial mate- 

 rials, in particular meteorites and lunar samples. Other re- 

 search involves the eatly conditions in the primitive solar 

 nebula; and, a computer program to calculate the abundances 

 of gases and solids as a function of the temperature, pressure, 

 and composition of material in any system in equilibrium. 



Research highlights for 1994 include: 



A new paradigm was established for relating properties of 

 meteorites formed in the primitive solar nebula to violent 

 events that are believed to have occurred when the solar sys- 

 tem formed. Confirmation and progressive refinements were 

 made of the orbit of Comet 1993c (Shoemaket-Levy) and the 

 circumstances of its collision with Jupiter in 1994. Separate 

 orbits were computed for 19 of the fragments, and the final 

 impact times could be predicted to an accuracy of about 

 10 minutes, enabling scientists worldwide, including a team 

 using an SAO-designed mftared camera in Hawaii, to observe, 

 record, and image the comet's impact with Jupiter. 



The Perseid comet Swift-Tuttle was found to be in reso- 

 nance with Jupiter, a situation that tends to stabilize the orbit 

 and make the object a potential threat to the Earth for at least 

 20000 years into the future. 



Preliminary analyses of Australian meteorite Calcalong 

 Creek, the first meteorite ftom the Moon to be found outside 

 Antarctica, showed it to contain a significant component of 

 KREEP (potassium, rare earth elements, and phosphorus) in 

 addition to fragments of highland and mare rocks found in 

 other lunar meteorites. 



The first discovery of olivine grains exsolved into fine Fe- 

 rich and Fe-poor lamellae was made in the Divnoe, Russia, 

 meteorite. The lamellae indicate slow cooling undet equilib- 

 rium conditions from about 1000 to 500 degrees C, at depth 

 within the parent body. 



In addition, the Central Bureau for Astronomical Tele- 

 grams and the Minor Planet Center introduced a new series of 

 Minor Planet Electronic Circulars to give more satisfactory 

 coverage to discoveries and follow-up of near-Earth objects, 

 which continue to be discovered in great profusion. 



Seven more transneptunian objects were discovered during 

 March-May. Like the objects found in September 1993, several 

 of these seem to be significantly closer to Neptune's orbit 

 than the original discoveries 1992 QBl and 1993 FW. 



Radio and Geoastronomy 

 Mark Reid, Associate Director 



Research in the Radio and Geoastronomy Division covers a 

 wide range of topics in radio astronomy, including the study 

 of the formation of stars, evolved stars, supernovae, the struc- 



48 



