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1.4. IAU colloquium no 112 on light pollution, radio interference and space debris
1.4. IAU COLLOQUIUM NO 112 ON LIGHT POLLUTION, RADIO INTERFERENCE AND SPACE DEBRIS3
Washington, DC, USA, August 1988 A 4-day colloquium, on Light Pollution, Radio Interference and Space Debris: The Increasing Environmental Impacts on Observational Astronomy, was held in Washington, DC, USA in mid-August 1988. The meeting was sponsored by the IAU and co-sponsored by URSI, COSPAR, and the Commission Internationale de 1’Eclairage (CIE). 78 papers were presented from among the 120 participants from 19 countries, including the USSR and the People’s Republic of China. There were numerous expressions of concern at the meeting that groundbased astronomical observatories around the world and future space observatories are jeopardized because of the proliferation of outdoor lighting, the burgeo~ng use of radio telecommunications, pa~icularly with space systems, and the growing amount of orbital debris generated by space activities. Light Pollution: Urban sky glow at some optical astronomy observatories is now at such a high level that closure is considered, and many sites will be seriously threatened over the next few decades. Speakers addressed the causes of and solutions to light pollution as it affects astronomy. Radio Inter&rence: Radio astronomers are interested in and have the capability of observing at frequencies ranging from appro~ately 20 MHz to 600 GHz from ground-based facilities. In order to study the faint cosmic emissions, radio-quiet frequency bands are required. While there are international organizations that regulate the allocation of r.f. bands and govern the assignment of frequencies to transmitters, commercial and other pressures for the use of such frequencies is so high that it is becoming increasingly difficult to preserve radio-quiet in those frequency bands considered most important to radio astronomers. Space-borne interference is an especially serious threat to radio astronomy because of its global character; there is little possibility of isolating an observatory at a remote location. At present, the frequency band from 1 to 3 GHz is of most concern to radio astronomers. Because of the transparency of the atmosphere, this band is ideally suited for satellite transmissions, and several systems, which potentially pose quite severe threats to radio astronomy, are in various stages of development or operation. The USSR’s Global Navigation Satellite System (GLONASS) is currently viewed as the number one global interference problem faced by radio astronomers. Its emissions interfere with observations of an important line of the hydroxyl molecule near 1600 MHz. Space Debris: The number of pieces of space debris is reputed to exceed Wrom URSI Information Bulletin No. 247, December 1988.
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the number of meteoroids, and the amount of space junk is growing with time. At present, only 5% of these objects in space larger than a metre or so in diameter are operational satellites. The rest of the objects are spent vehicles or space debris. By the 1990s the debris population will become so large that collisions among the debris will be frequent, creating more ~agments and yet more collisions. Space debris is an obvious threat to the health of orbiting observatories because of the danger of collisions. Orbiting objects also impact ground-based observatories; practically every photograph taken with certain fundamental survey telescopes is marred by light streaks due to satellites or space debris. Because of the danger to active space missions, there is reason to believe that the space faring nations will have to take steps to control satellite debris for purely operational reasons. At the Colloquium, it was generally concluded that through its own activities mankind is losing its view of the universe. Sensitivity to environmental issues such as light pollution, radio interference and space debris must be heightened, just as the environmental impacts of air pollution, water pollution, and toxic waste and the protection of natural resources have been publicized and solutions sought.
1.5. SY~~SIU~
ON THE SElSlWOl.OGY OF THE SUN AND SUN-LIKE STARS4
Puerto de la Cruz (Tenerife), Spain, 26-30 September 1988 The Symposium on the Seismology of the Sun and Sun-like Stars, held in Puerto de la Cruz, September 1988, was jointly organized by ESA and the Instituto de Astroffsica de Canarias (IAC). In line with earlier meetings in Aarhus (1986), Catania (1983) and the Crimea (1981), the purpose was to bring together the experimenters who are preparing the ground-based networks and future space programmes with the helio- and astero-seismology community to exchange ideas and results. The meeting was timed to coincide with the definition phase of several second-generation experiments, and aimed to create an atmosphere in which experience and future plans could be shared. The combination of ground and space observations that will be available in the next decade, as well as the theoretical work that is being plarmed, is bound to produce a turning point in the understanding of the solar interior. Similarly, with the extension of helioseismology techniques to other stars and growing experimental effort, major bre~~roughs in the underst~ding of stellar (and solar) interiors can be foreseen in the near future. @)From ESA Journal Vol. 12 No. 3,1988.
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Washington, DC, USA, August 1988 A 4-day colloquium, on Light Pollution, Radio Interference and Space Debris: The Increasing Environmental Impacts on Observational Astronomy, was held in Washington, DC, USA in mid-August 1988. The meeting was sponsored by the IAU and co-sponsored by URSI, COSPAR, and the Commission Internationale de 1’Eclairage (CIE). 78 papers were presented from among the 120 participants from 19 countries, including the USSR and the People’s Republic of China. There were numerous expressions of concern at the meeting that groundbased astronomical observatories around the world and future space observatories are jeopardized because of the proliferation of outdoor lighting, the burgeo~ng use of radio telecommunications, pa~icularly with space systems, and the growing amount of orbital debris generated by space activities. Light Pollution: Urban sky glow at some optical astronomy observatories is now at such a high level that closure is considered, and many sites will be seriously threatened over the next few decades. Speakers addressed the causes of and solutions to light pollution as it affects astronomy. Radio Inter&rence: Radio astronomers are interested in and have the capability of observing at frequencies ranging from appro~ately 20 MHz to 600 GHz from ground-based facilities. In order to study the faint cosmic emissions, radio-quiet frequency bands are required. While there are international organizations that regulate the allocation of r.f. bands and govern the assignment of frequencies to transmitters, commercial and other pressures for the use of such frequencies is so high that it is becoming increasingly difficult to preserve radio-quiet in those frequency bands considered most important to radio astronomers. Space-borne interference is an especially serious threat to radio astronomy because of its global character; there is little possibility of isolating an observatory at a remote location. At present, the frequency band from 1 to 3 GHz is of most concern to radio astronomers. Because of the transparency of the atmosphere, this band is ideally suited for satellite transmissions, and several systems, which potentially pose quite severe threats to radio astronomy, are in various stages of development or operation. The USSR’s Global Navigation Satellite System (GLONASS) is currently viewed as the number one global interference problem faced by radio astronomers. Its emissions interfere with observations of an important line of the hydroxyl molecule near 1600 MHz. Space Debris: The number of pieces of space debris is reputed to exceed Wrom URSI Information Bulletin No. 247, December 1988.
9
the number of meteoroids, and the amount of space junk is growing with time. At present, only 5% of these objects in space larger than a metre or so in diameter are operational satellites. The rest of the objects are spent vehicles or space debris. By the 1990s the debris population will become so large that collisions among the debris will be frequent, creating more ~agments and yet more collisions. Space debris is an obvious threat to the health of orbiting observatories because of the danger of collisions. Orbiting objects also impact ground-based observatories; practically every photograph taken with certain fundamental survey telescopes is marred by light streaks due to satellites or space debris. Because of the danger to active space missions, there is reason to believe that the space faring nations will have to take steps to control satellite debris for purely operational reasons. At the Colloquium, it was generally concluded that through its own activities mankind is losing its view of the universe. Sensitivity to environmental issues such as light pollution, radio interference and space debris must be heightened, just as the environmental impacts of air pollution, water pollution, and toxic waste and the protection of natural resources have been publicized and solutions sought.
1.5. SY~~SIU~
ON THE SElSlWOl.OGY OF THE SUN AND SUN-LIKE STARS4
Puerto de la Cruz (Tenerife), Spain, 26-30 September 1988 The Symposium on the Seismology of the Sun and Sun-like Stars, held in Puerto de la Cruz, September 1988, was jointly organized by ESA and the Instituto de Astroffsica de Canarias (IAC). In line with earlier meetings in Aarhus (1986), Catania (1983) and the Crimea (1981), the purpose was to bring together the experimenters who are preparing the ground-based networks and future space programmes with the helio- and astero-seismology community to exchange ideas and results. The meeting was timed to coincide with the definition phase of several second-generation experiments, and aimed to create an atmosphere in which experience and future plans could be shared. The combination of ground and space observations that will be available in the next decade, as well as the theoretical work that is being plarmed, is bound to produce a turning point in the understanding of the solar interior. Similarly, with the extension of helioseismology techniques to other stars and growing experimental effort, major bre~~roughs in the underst~ding of stellar (and solar) interiors can be foreseen in the near future. @)From ESA Journal Vol. 12 No. 3,1988.
10