Richard M. West

The Rotation Period of C/1995 O1 (Hale-Bopp)

C/1995 O1 (Hale-Bopp) was observed in daylight on 16 days between 1997 April 1 and 1997 April 28, five of which had long time sequences (up to 10 hr of data), using the near infrared CAIN camera on the 1.5 m Carlos Sanchez Telescope at Teide Observatory (Tenerife, Canary Islands, Spain). Three spiral dust jet structures were observed for several almost complete rotations. A nucleus rotation period of 11.34±0.02 hr was determined from two different methods. No variations of the rotation period with time due to precessional effects were found in our data. However, the time sampling of the observations, similar to the suggested spin precession period, prevents us from ascertaining whether such variations exist. We note, though, that the good agreement of our results with the rotation periods at different epochs reported by other groups suggests that if they exist, these variations must be small, hence the rotation cannot be very complex.

Public Outreach in Astronomy: The ESO Experience

Public communication of astronomy can play an important role in the continued effort to enhance public awareness of science. To achieve success, however, it is necessary to define clear communication goals, to identify the target constituencies and select the appropriate means of communication, e.g. the World-Wide Web, the public mass media, etc. Each of them offer possibilities, albeit with a number of limitations. Using examples from the ESO outreach activities, we describe how various communication channels can be used in combination to obtain the desired results. These activities are not restricted to day-to-day communication, but include dedicated educational programmes with long-term effects.

Dust Morphology Of Comet Hale-Bopp (C/1995 O1): I. Pre-Perihelion Coma Structures In

In 1996 comet Hale-Bopp exhibited a porcupine-like coma with straight jets of dust emission from several active regions on the nucleus. The multi-jet coma geometry developed during the first half of 1996. While the jet orientation remained almost constant over months, the relative intensity of the jets changed with time. By using the embedded fan model of Sekanina and Boehnhardt (1997a) the jet pattern of comet Hale-Bopp in 1996 can be interpreted as boundaries of dust emission cones (fans) from four — possibly five — active regions on the nucleus (for a numerical modelling see part II of the paper by Sekanina and Boehnhardt, 1997b).

The ESO Sky Surveys

Technical aspects of the production of photographic Sky Surveys and Atlasses are discussed. The need to optimize all factors, e.g. telescope site, telescope optics, mechanics and control system, hypersensitization, calibration, processing and reproduction is illustrated by the ESO Im Schmidt telescope and the ESO Sky Surveys.

DIVISION III / WORKING GROUP COMMITTEE ON SMALL BODIES NOMENCLATURE

A total of 701 comets received names between July 2005 and June 2008. Comets observed only from the SOHO and STEREO missions, as well as further comets recognized from the long-defunct SOLWIND satellite, accounted for 520 of these names.

“The Forest and the Trees” — Summary of an Atacama Workshop

This intriguing title was chosen not by me, but by the Chairman of the Scientific Organizing Committee with reference to Fred Whipple’s talk at the Heidelberg Conference on Halley in 1989. It may seem a bit strange in the middle of the dry Atacama region, but if we would have had a conference about small objects in the outer solar system at that time, 14 years ago, there would have been about as much to talk about as there are trees beyond the mountains surrounding the city of Antofagasta.

Physical studies of KuiperBelt objects: an ESO VLT large program

Since April 2001 a Large Program for the study of physical properties of Trans-Neptunian Objects (TNO) and Centaurs is underway at the Paranal (Very Large Telescope VLT) and La Silla (New Technology Telescope NTT) observatories of the European Southern Observatory (ESO) in Chile. Combining service (SM) and visitor mode (VM) observations multi-wavelength imaging (BVRIJHK filters) and low-dispersion spectroscopy is performed in the visible and near-IR on a sample of objects that should allow a better and more consistent taxonomic characterization and classification of these pristine bodies in our solar system. Starting with a summary of the current knowledge on the Kuiper-Belt and the populations of objects, the paper presents the goals of this project and its scientific and organizational implementation. It illustrates the progress and the scientific achievements by a hynoptic view of results from photometry and spectroscopy of these Solar System objects.

Tycho and his observatory as sources of inspiration to modern astronomy

This article briefly surveys the life and scientific work of Tycho Brahe (1546 - 1601), one of the greatest astronomers of all times. He successfully designed and constructed the most advanced astronomical observatory of his time on the island of Hven and during twenty years he effectively directed what is considered to be the first, modern research institute. He inaugurated a new era of observational astronomy and emphasized the need to determine instrumental errors, just before this field of natural science was revolutionized by the invention of the telescope. He laid the observational basis for Keplers investigations of the planetary motions which eventually served as a cornerstone for Newtons description of the universal force of gravitation. Tychos challenges were similar to those of his colleagues of our days and it is of some interest to understand the environment in which he operated and the keys to his success.

Summary of Conference

The recent apparition of comet Hale-Bopp has provided the first opportunity to study a truely “Great Comet” with modern observational equipment, from ground and from space. An enormous amount of data was gathered and is still in the process of being analysed. When compared with elaborate and realistic theoretical considerations, important new insights are now being obtained into the complex physical and chemical processes in the cometary environment. This summary highlights some of the main achievements of this work, as they were presented at the first major international conference on comet Hale-Bopp in February 1998.

Very Distant Objects in the Solar System

We discuss photometric and spectroscopic observations of very faint and distant minor objects in the Solar System that will become possible with the ESO Very Large Telescope (VLT). The proposed studies are based on extrapolations from recent, related pilot programmes at the performance limits of present observational facilities, notably the 3.58-metre ESO New Technology Telescope with associated instrumentation (EMMI and SUSI). The VLT observations will most certainly have a major impact on future studies of physical processes in hitherto inaccessible reaches of the outer solar system and, thus, on the continued investigation of its origin and early evolution.