Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from hogtown.andrew.cmu.edu via trymail for +dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl@andrew.cmu.edu (->+dist+/afs/andrew.cmu.edu/usr11/tm2b/space/space.dl) (->ota+space.digests) ID ; Mon, 24 Jun 91 06:19:40 -0400 (EDT) Message-ID: Precedence: junk Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Mon, 24 Jun 91 06:19:35 -0400 (EDT) Subject: SPACE Digest V13 #702 SPACE Digest Volume 13 : Issue 702 Today's Topics: Electronic Journal of the ASA - June 1991 Administrivia: Submissions to the SPACE Digest/sci.space should be mailed to space+@andrew.cmu.edu. Other mail, esp. [un]subscription requests, should be sent to space-request+@andrew.cmu.edu, or, if urgent, to tm2b+@andrew.cmu.edu ---------------------------------------------------------------------- Date: 6 Jun 91 15:20:29 GMT From: nntpd.lkg.dec.com!rburns.enet.dec.com!klaes@decuac.dec.com (Larry Klaes) Subject: Electronic Journal of the ASA - June 1991 THE ELECTRONIC JOURNAL OF THE ASTRONOMICAL SOCIETY OF THE ATLANTIC Volume 2, Number 11 - June 1991 ########################### TABLE OF CONTENTS ########################### * ASA Membership/Article Submission Information * Sir William Herschel and the Natural History of the Heavens - Keith M. Parsons * Curbing Light Pollution in Ohio - Robert Bunge ########################### ASA MEMBERSHIP INFORMATION The Electronic Journal of the Astronomical Society of the Atlantic (EJASA) is published monthly by the Astronomical Society of the Atlantic, Inc. The ASA is a non-profit organization dedicated to the advancement of amateur and professional astronomy and space exploration, and to the social and educational needs of its members. ASA membership application is open to all with an interest in astronomy and space exploration. Members receive the Journal of the ASA (hardcopy sent through U.S. Mail), the Astronomical League's REFLECTOR magazine, and may additionally purchase discount subscrip- tions to ASTRONOMY, DEEP SKY, ODYSSEY, SKY & TELESCOPE, and TELESCOPE MAKING magazines. For information on membership, you may contact the Society at any of the following addresses: Astronomical Society of the Atlantic (ASA) c/o Center for High Angular Resolution Astronomy (CHARA) Georgia State University (GSU) Atlanta, Georgia 30303 U.S.A. asa@chara.gsu.edu ASA BBS: (404) 985-0408, 300/1200 Baud. or telephone the Society Recording at (404) 264-0451 to leave your address and/or receive the latest Society news. ASA Officers and Council - President - Don Barry Vice President - Nils Turner Secretary - Ken Poshedly Treasurer - Alan Fleming Board of Advisors - Edward Albin, Bill Bagnuolo, Jim Bitsko Council - Jim Bitsko, Bill Crane, Toni Douglas, Eric Greene, Larry Klaes, Tano Scigliano, Bob Vickers, Michael Wiggs, Rob Williams ARTICLE SUBMISSIONS - Article submissions to the EJASA on astronomy and space exploration are most welcome. Please send your on-line articles in ASCII format to Larry Klaes, EJASA Editor, at the following net addresses or the above Society addresses: klaes@rburns.enet.dec.com or - ...!decwrl!rburns.enet.dec.com!klaes or - klaes%rburns.dec@decwrl.enet.dec.com or - klaes%rburns.enet.dec.com@uunet.uu.net You may also use the above net addresses for EJASA backissue requests, letters to the editor, and ASA membership information. When sending your article submissions, please be certain to include either a network or regular mail address where you can be reached, a telephone number, and a brief biographical sketch. DISCLAIMER - Submissions are welcome for consideration. Articles submitted, unless otherwise stated, become the property of the Astronomical Society of the Atlantic, Inc. Though the articles will not be used for profit, they are subject to editing, abridgment, and other changes. Copying or reprinting of the EJASA, in part or in whole, is encouraged, provided clear attribution is made to the Astronomical Society of the Atlantic, the Electronic Journal, and the author(s). This Journal is Copyright (c) 1991 by the Astronomical Society of the Atlantic, Inc. SIR WILLIAM HERSCHEL AND THE NATURAL HISTORY OF THE HEAVENS by Keith M. Parsons In the book TIMAEUS, the Greek philosopher Plato (circa 427-347 B.C.) tells us that the Demiurge, the deity of the material world, patterned existence after the eternal forms. However, the perfection of an eternal being cannot be completely conferred upon a generated thing, so the heavens were made "a moving likeness of eternity." In other words, since a physical universe must be subject to motion, the best sort of motion is everlastingly the same. Thus, the heavens, which move endlessly in perfect circles, are as close to the change- less perfection of the forms as a created thing can be. No view could be more alien to the universe of contemporary astronomy than such a picture of serene, changeless perfection. We now know that stars are born and die, that celestial events are turbulent and frequently violent, and indeed, that the Universe itself is expanding and evolving. This vast change of cosmic perspective was, of course, the product of centuries of labor by many different persons. However, as long as astronomy's attention was focused on the planets, moons, and comets of Earth's solar system - which it was until well after Sir Isaac Newton's (1642-1727) day - the evolutionary concept of the Universe could make little headway. Despite German philosopher Immanuel Kant's (1724-1804) prescient speculations, it was only when the British astronomer Sir William Herschel (1738-1822) began the systematic study of the stars and nebulae did the natural history of the heavens become possible. Astronomers had long been aware of faint, diffuse patches of luminosity scattered among the sharp, point-like lights of the stars. Before Herschel, few astronomers had shown much interest in such nebulae. Many, like Charles Messier (1730-1817), regarded them as a nuisance; Messier's famous catalogue of the nebulae was intended to help comet hunters avoid misidentifying nebulae as new comets. Herschel, by making for himself the best telescopes that had yet been available for astronomers, was able to make an important dis- covery, which he announced in a paper read to Great Britain's Royal Astronomical Society (RAS) on June 17, 1784: "The excellent collection of nebulae and clusters of stars which has lately been given in the CONNOISSANCE DE TEMPS for 1783 and 1784 [Messier's Catalogue], lead me next to a subject which, indeed, must open a new view of the heavens. As soon as these volumes came into my hands, I applied my former 20-foot [six-meter] reflector of 12 inches [thirty centimeters] aperture to them and saw, with the greatest pleasure, that most of the nebulae, which I had the opportunity of examining in proper situations, yielded to the force of my light and power, and were resolved into stars." Herschel then states that many of the nebulae regarded by Messier as without stars had either been definitely resolved into stars or gave every indication that they could be so resolved. Herschel was overly optimistic; some of the nebulae he mentions are, in fact, galaxies and not so resolvable into stars by any of Herschel's telescopes. Other nebulae, such as Messier 1 (M1, now known as the Crab Nebula, the remnant of a supernova first seen on Earth in 1054 A.D.), are in fact, non-stellar and are constituted of diffuse clouds of glowing gas. Herschel, of course, had no way of knowing that the Messier objects would ultimately turn out to be so diverse (they are now recognized to comprise globular clusters, open clusters, galaxies, planetary nebulae, supernova remnants, and several other types of celestial objects). Hence, it was reasonable to hypothesize, as Herschel did at first, that all nebulae would prove resolvable as more and more powerful telescopes were built. In a paper delivered to the Royal Astronomical Society less than one year after the one quoted above, Herschel proposed that the nebulae are formed when randomly scattered stars are drawn together through mutual gravitational attraction. Herschel, in a remarkable passage, imagined an observer's expanding conception of the Universe. At first, the observer will think that the entire Universe is contained in a few constellations. He will see the light of distant stars as only a milky luminosity. But, says Herschel, let him now have use of a telescope: "...he begins to suspect that all the milkiness of the bright path which surrounds the sphere may be owing to stars....He now increases his power of vision and, applying himself to a close observation, finds that the milky way is indeed a collection of very small stars. He perceives that those objects which had been called nebulae are evidently nothing but cluster of stars....He forms the idea of immense strata of fixed stars, of clusters of stars and nebulae." Indeed, says Herschel, the observer will conclude that he inhabits only a single cluster, not necessarily the largest, in this vast system of clusters upon clusters upon clusters. It is remarkable to see how easily Herschel accepts the concept of a Universe of previously unimaginable vastness. It is even more remarkable to see the degree to which he anticipates contemporary cosmology with its talk of clusters and superclusters and galaxies. Nevertheless, Herschel came to realize that his scheme was simplistic and did not square with certain phenomena. In fact, some nebulae simply did not appear to be of a starry nature. The Great Nebula in the constellation of Orion the Hunter, for instance, is so extensive that, if it is so far away that even Herschel's largest telescope cannot resolve it into stars, its actual size must be unreasonably huge even by Herschel's standards. Further, Herschel had observed a number of what today are called "planetary" nebulae. These nebulae, constituted of matter shed by old, giant stars, frequently take the form of a nebulous ring surrounding a bright star in the center. Herschel concluded that if the nebulosity in this case is caused by the concentration of distant stars, those stars must be much smaller than the central star. Indeed, either the central object is so huge, or the surrounding ones so small, that one or the other should not be considered of stellar nature. Herschel therefore concluded that there are cases of true nebulosity, i.e., that some nebulae are not stellar but are constituted of a "shining fluid" of unknown nature. Herschel sought to incorporate true nebulae into his evolutionary scheme. By 1811, he believed he had succeeded. Numerous observations had convinced him that the nebulae formed a graded series with coarse star clusters (such as the Pleiades) at one end and extensive, diffuse nebulosities (such as the Great Nebula in Orion) at the other end. Further, between these extremes, Herschel believed that he had observed every possible gradation of nebulae types. He therefore concluded that this series constituted an evolutionary sequence: Diffuse nebulae gradually condense to form stars which then, through the action of mutual gravitation, join with other stars to form clusters of various sorts. Herschel now believed he had a true natural history of the heavens. In one famous passage, he compares the Universe to a luxuriant garden in which we may find the greatest variety of productions flourishing in different beds. Further, we see specimens in every stage of growth, maturity, and decay, so we know their natural history just as if we had watched a single specimen pass through these stages. According to Herschel, we therefore, inhabit a dynamic Universe that evolves over great spaces and vast stretches of time. Herschel was ultimately wrong, of course, in placing all nebulae in a single evolutionary sequence. As mentioned earlier, many diffe- rent types of objects were called "nebulae" in Herschel's day. Never- theless, Herschel's evolutionary approach was a fruitful one, and much subsequent astronomy can be viewed as a series of emendations or footnotes to his scheme. For instance, that stars are formed from condensing clouds of gas and dust is a tenet of contemporary astronomy; the Orion Nebula itself is believed to be such a stellar nursery. Herschel oversimplified, which is only to be expected when work on a major problem is just getting started, but his basic insights were sound. Herschel was an enormous success, both as a theoretician and an observer. He also discovered the planet Uranus in 1781, infrared radiation, and binary star systems. One thing his success did show is that there is a place for the methods and practices of natural history, even within a highly theoretical science. It was Herschel's skill as a natural historian, the astonishing patience and thoroughness he displayed in his systematic surveys of the whole sky, that provided the massive amounts of observational data he used to back up his theor- ies. More than that, Herschel showed that the simple desire to observe carefully and describe accurately, plus the willingness to abandon hypotheses in the light of new evidence, are indeed virtues conducive to the highest scientific achievement. References and Further Reading - Berry, Arthur, A SHORT HISTORY OF THE HEAVENS, Dover Publica- tions, New York, 1961 Herschel, Sir William (Michael Hoskins, editor), WILLIAM HERSCHEL AND THE CONSTRUCTION OF THE HEAVENS, Oldbourne Book Co., London, 1963 Kant, Immanuel, UNIVERSAL NATURAL HISTORY AND THEORY OF THE HEAVENS, 1755 About the Author - Keith Parsons earned his first Ph.D. in the Philosophy of Religion, which led to an academic career. Keith later chose to leave this pro- fession to earn a second Ph.D. in the Philosophy of Science, which he is currently pursuing at the University of Pittsburgh in Pennsylvania. Keith's interests have led to a strong interaction with members of the Center for High Angular Resolution Astronomy (CHARA) and an interest in skeptical inquiry and philosophy of the scientific method. CURBING LIGHT POLLUTION IN OHIO by Robert Bunge What are, perhaps, the first light regulations in Ohio were passed in early April of 1991 by the zoning committee of Liberty Township in Delaware County. Perkins Observatory, one-time location of the largest telescope east of the Mississippi River, a 173-centimeter (69-inch) reflector now in Flagstaff, Arizona, and current home of the "Big Ear" radio telescope, are located in Liberty Township. These regulations are the brainchild of Doctor Robert Dixon, assistant director of the Big Ear radio telescope. Dixon, a resident of Liberty Township, served on a zoning committee that made suggestions for controls to handle rapid growth in the forty-kilometer (twenty- five-mile) wide township to the township zoning board, which then sorted through the suggestions and started the long process that turns them into law. Dixon's proposed lighting regulations received support from the zoning board once they understood the problem of light pollution. The passing of these laws is an important victory for lovers of the night sky in Ohio, not only because of the location of Perkins Observatory, site of a recent series of highly successful public programs conducted by the Columbus Astronomical Society, but also because the county is the primary target of rapid growth from the nearby state capital of Columbus to the south. Recent trends in expansion from Columbus have been knocking on the doors of Delaware County over the course of the past five years. While much of the new construction does use full-cut off, or fully shielded, lighting fixtures, much more does not. The timing for the new laws was critical. As Dixon pointed out, zoning laws are difficult to change. It requires public hearings, lawyers, and much discussion to make even a small change. As a result, many smaller towns, counties, and townships only make zoning changes every few years. The new lighting laws in Liberty Township were only a small part of a much larger rewrite of the zoning laws. Thus, the time to approach a township to write in lighting controls is not just after they have made changes, but before they do so. The new Liberty Township regulations require that all outdoor lighting in the township be pointed downward and fully shielded. This not only helps reduce light pollution, but also light trespass, which is when light from a neighbor is allowed to shine onto another's property. The regulations also require that outdoor lighting not actually being used for practicable purposes be turned off at 11:00 p.m.. Even though most astronomers would consider these controls to be reasonable, many people have a difficult time, at first, in under- standing them. Dixon said when he first proposed the regulations, there was a good bit of opposition, ranging from churches interested in lighting their buildings to patriots who were interested in flying the United States flag all night. To answer these arguments, Dixon used a tried and true technique when it comes to getting things done in low-level government: Public speaking. Dixon arranged to give presentations to local groups and at public hearings that were held on the new regulations. As a tool to assist the effort, he used slides that are designed to present the problem of light pollution to the general public, sold by the Astronomical Society of the Pacific (ASP). "I could have talked and talked, but without those slides I would have never convinced many people," Dixon said. By the time the regulations were up for a final vote by the zoning board, the only opposition was that regulating lighting was "going too far". "Most people who live in Liberty Township do so because they want to live in the country. A dark sky is part of being in the country, so few people were opposed to (the regulations) once they understood them," Dixon said. The wording and general directions of the regulations were patterned after those suggested by the International Dark-Sky Association, an organization of persons interested in preserving the night sky and saving energy, said Dixon. Dixon is not ready to stop yet. He hopes to expand the controls to nearby townships and cities as they try to revamp their zoning laws in the near future. Resources - Astronomical Society of the Pacific (ASP) Catalog Department 390 Ashton Avenue San Francisco, California 94112 U.S.A. Slide set - AS 294, $19.95 LIGHT POLLUTION: PROBLEMS AND SOLUTIONS International Dark-Sky Association 3545 North Steward Tucson, Arizona 85716 U.S.A. Individual membership - $20.00 (Can accept Master/Visa Card) IRS registered 501-c-3 non-profit organization ----------------------------------------------------------------- The Lighting Regulations of Liberty Township, Delaware County, Ohio Section 21.04 - Lighting Regulations 1. GENERAL REQUIREMENTS - All lighting shall be controlled in such a way as to not shine up into the sky or onto any neighboring properties. Examples of ways in which this shall be accomplished are: a) Use of fully shielded cut-off fixtures; b) Directing light fixtures downward rather than upward; c) Shielding the light in such a way that the light emitting portion of the fixture cannot be seen at a reasonable distance. 2. SPECIFIC REQUIREMENTS a) Where used for security purposes or to illuminate walkways, roadways, equipment yards, and parking lots, only fully shielded cut-off style outdoor light fixtures shall be utilized. b) Where used for signs or for decorative effects or recreational facilities, such as for building, landscape, or ballfield illumination, the outdoor light fixtures shall be equipped with automatic timing devices and shielded and focused to minimize light pollution. c) All outdoor light fixtures installed and maintained upon private property within all zoning districts shall be turned off between 11:00 P.M. and Sunrise EXCEPT when used for security purposes or to illuminate walkways, roadways, equipment yards, and parking lots. d) All illuminated signs for commercial purposes shall be turned off between 11:00 P.M. and Sunrise, EXCEPT that signs may be illuminated while the business facility is open to the public. All forms of flashing, rotating, moving, or digital lights shall be prohibited. e) All outdoor light pole fixtures shall not exceed a maximum height of nine (9) meters (thirty (30) feet). f) In addition to the provisions of this Article all outdoor light fixtures shall be installed in conformity with all other applicable provisions of this Resolution. 3. EXEMPTIONS a) All outdoor light fixtures producing light directly by the combustion of fossil fuels, such as kerosene lanterns or gas lamps, are exempt from the requirements of this Section. b) All low-voltage lighting and holiday lighting shall be exempt from the requirements of this Section. ----------------------------------------------------------------- Related EJASA articles - "Stopping Space and Light Pollution", Larry Klaes and Phil Karn - September 1989 "When the Light Gets in Your Eyes, You Shouldn't Have to Drive to the Country", James Smith and Ken Poshedly - February 1991 About the Author - Robert Bunge is an amateur astronomer and telescope builder, originally from Columbus, Ohio, who likes to observe all types of objects. Robert has had articles published in ASTRONOMY, SKY & TELESCOPE, and TELESCOPE MAKING magazine. Robert is a contributing editor for DEEP SKY magazine. Robert may be contacted at Internet address bunge@wam.umd.edu Robert is the author of "Stephan's Quintet" in the February 1991 issue of the EJASA. THE ELECTRONIC JOURNAL OF THE ASTRONOMICAL SOCIETY OF THE ATLANTIC June 1991 - Vol. 2, No. 11 Copyright (c) 1991 - ASA ------------------------------ End of SPACE Digest V13 #702 *******************