Return-path: X-Andrew-Authenticated-as: 7997;andrew.cmu.edu;Ted Anderson Received: from beak.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 ; Wed, 4 Apr 90 02:14:51 -0400 (EDT) Message-ID: Reply-To: space+@Andrew.CMU.EDU From: space-request+@Andrew.CMU.EDU To: space+@Andrew.CMU.EDU Date: Wed, 4 Apr 90 02:14:21 -0400 (EDT) Subject: SPACE Digest V11 #216 SPACE Digest Volume 11 : Issue 216 Today's Topics: Electronic Journal of the ASA, Vol. I, No. IX ---------------------------------------------------------------------- Date: 3 Apr 90 03:41:28 GMT From: mephisto!eedsp!chara!don@handies.ucar.edu (Donald J. Barry) Subject: Electronic Journal of the ASA, Vol. I, No. IX THE ELECTRONIC JOURNAL OF THE ASTRONOMICAL SOCIETY OF THE ATLANTIC Volume 1, Number 9 - April 1990 ########################### TABLE OF CONTENTS ########################### * ASA Membership/Article Submission Information * Amateur Astronomy in Spain - Jordi Iparraguirre * The Cosmic Distance Scale - Eric Greene * Milton Updegraff, Astronomer - Darwin Christy ########################### 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. Membership application is open to all with an interest in astronomy and space exploration. Members receive the ASA Journal (hardcopy sent through U.S. Mail), the Astronomical League's REFLECTOR magazine, and may additionally purchase discount subscriptions to SKY & TELESCOPE, ASTRONOMY, DEEP SKY, and TELESCOPE MAKING magazines. For information on membership, contact the Society at: 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@gatech.edu or asa@chara.uucp 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 - Bill Bagnuolo Secretary - Ken Poshedly Treasurer - Alan Fleming Board of Advisors - Bill Hartkopf, Edward Albin, Jim Bitsko Council: Larry Klaes, Michael Wiggs, Max Mirot, Eric Greene, Patti Provost, Paul Pirillo, Becky Long, Jim Bitsko, Julian Crusselle, Toni Douglas ARTICLE SUBMISSIONS - Article submissions on astronomy and space exploration to the EJASA 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@wrksys.dec.com, or ...!decwrl!wrksys.dec.com!klaes, or klaes%wrksys.dec@decwrl.dec.com, or klaes@wrksys.enet.dec.com, or klaes%wrksys.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. 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. 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) 1990 by the Astronomical Society of the Atlantic. AMATEUR ASTRONOMY IN SPAIN by Jordi Iparraguirre For centuries Spain was not a major participant in the expanding fields of astronomy and astrophysics so prominent among some of its European neighbors. This situation began to change in the early 1970s when several European nations decided to build their best astronomical observatories in the Canary Islands off the coast of Morocco. This enterprise dramatically increased the number of Spanish astronomy students and research projects in the science, as Spanish astronomers receive a large portion of the scheduled observing time. As with so many other nations, the introduction of professional astronomy in Spain eventually led to the growth of many amateur organizations. The man considered most responsible for bringing amateur astronomy to fruition in Spain was Josep Comas i Sola (1868-1937). Comas i Sola was a Catalan astronomer and the director of the Observatori Fabra in Barcelona. He discovered eleven planetoids [1] and a periodic comet subsequently named after him. [2] This astronomer is said to have been the first to detect a "diffuse edge" around Titan, the largest moon of the planet Saturn. [3] This "edge" was caused by Titan's thick atmosphere, which was not officially confirmed until 1944 by the American astronomer Gerard P. Kuiper (1905-1973). [4] Comas i Sola is regarded by many Spanish amateurs as the foremost astronomy popularizer of their country. Josep Comas i Sola founded one of the first amateur astronomical associations in Spain in 1911 called SADEYA (Sociedad Astronomica de Espana y America - the Astronomical Society of Spain and [South] America). [5] At present the primary activity of this group is to produce a monthly star chart and ephemeras published in LA VANGUARDIA (The Vanguard), one of the most important newspapers in Spain. In 1948, members from SADEYA founded ASTER (Agrupacio Astronomica de Barcelona - the Astronomical Society of Barcelona; ASTER is the Greek word for "star"). ASTER has become one of the most active astronomy associations in Spain. They were one of the first non- professional teams to pick up the radio transmissions of the Soviet satellite SPUTNIK 1 as it orbited Earth in 1957. ASTER members also had the good fortune to be visited by the famous German rocket pioneer Hermann Oberth (1894-1989) and the Soviet scientist Leonid Sedov (Chief engineer on the SPUTNIK project) in October of 1957 at the International Astronomical Union (IAU) meeting held in Barcelona. Today, ASTER follows the solar observing program lead by SONNE, a West German association dedicated to observing the Sun (Sonne is the German word for Sun). We send our observations of variable stars to AFOEV (Associacion Francoise d'Observateurs d'Estels Variables - the French Association of Variable Star Observers) and AAVSO (American Association of Variable Star Observers). In the summer of 1989, ASTER members observed the major fading of the giant gas planet Jupiter's South Equatorial Belt [6]. Some of the main activities in ASTER are solar and planetary monitoring (Association of Lunar and Planetary Observers, ALPO), astrophotography (reprophotography and hypersensi- tized films), occultations, variable stars, and divulgation (popular- izing astronomy, teaching courses, and collaborating with the news media on events in the field). In 1960, a number of ASTER members founded Agrupacio Astronomica de Sabadell (Sabadell is a town near Barcelona). A. A. Sabadell has several delegations across Spain. Its prominent member is Josep Costas, who is known for his experience at observing the Sun (he has been studying Earth's star for fifty years) and telescope-making (Costas has made more than two thousand mirrors). A. A. Sabadell's main activities are divulgation, occultations (European Asteroidal Occultations Network, EAON) [7], and solar observation. GEA (Grup d'Estudis Astronomics, the Astronomical Studies Group) was created in 1983 when a group of people from ASTER and A. A. Sabadell decided to work at more professional levels. GEA is mainly composed of professional astronomers, astronomy undergraduate students and graduates, and highly skilled amateurs. GEA's director is Josep M. Gomez, who recently discovered that SAO 139174 is both an eclipsing binary star and one of the one hundred brightest known variable stars. GEA leads the Spanish wing of IAPPP (International Amateur Professional Photoelectric Photometry). GEA collaborates with IAPPP, EAON, and ALPO. Its principal observing site is in the Pyrenees Mountains. Each summer, ASTER and several other groups are given the opportunity to use the GEA's fifty-centimeter (twenty-inch) telescope, as well as their two forty-centimeter (sixteen-inch) and four twenty-centimeter (eight-inch) Celestron and Meade. These opportunities greatly help to improve the skills and knowledge of the groups. Gomez is considered by many to be the most important amateur- professional astronomer in Spain today. His main interests of study are the atmosphere of Jupiter, photometric photometry, and solar phenomena. GEA projects involve CCD (Charge-Coupled Device) imaging and software analysis in order to get high-resolution planetary images. Red Mira is a network of different associations that follow the same observing program on variable stars. Their observations are sent to AAVSO and AFOEV. There are a number of other astronomical groups in Spain, some of which you will find in the list near the end of this article. The oldest and most active associations are located in Catalonia. In 1976, ASTER organized the first national amateur meeting in Barcelona. Since then, these meetings have been organized by other associations in different cities every two years. In 1987, the meeting returned to Barcelona (organized by SADEYA) and was focused on honoring Josep Comas i Sola on the fiftieth anniversary of his death. The latest meeting, held in Madrid, joined amateurs and professionals from more than seventy astronomy groups all over Spain. There are two monthly astronomy magazines published in Spain: TRIBUNA DE ASTRONOMIA and ASTRONOMIA, ASTROFOTOGRAFIA Y ASTRONAUTICA. They often publish photographs and articles written by skilled amateurs. Since July of 1989, ASTER has begun to lead the e-mail commu- nications field in Spain. We recently got in touch with a team of young businessmen interested in this area, thinking that e-mail could be a useful tool for the group. Their system is called NEXUS. It has the same software as BIX. Though having been in operation for only one year now, NEXUS has given us the opportunity to moderate a forum of astronomical topics and have our own e-mail address. This public forum allows us to talk about astronomy to a wide variety of people in many different fields. ASTER has another private forum for associations and their members with which we share ephemeras data, answer questions about astronomy, present observing programs, and collect data. ASTER also posts alerts regarding such events as comet hunts and variable star reports. Our plan is to eventually join together as many Spanish amateur astronomy associations as possible and try to connect to other asso- ciations from around the globe. In fact, last summer ASTER wrote a letter to several other European amateur associations explaining our situation and future planning. Don Miles, editor for the Electronic Circular of the British Astronomical Association (BAA), answered us. He is connected to Microlink Gold. We have heard that some Italian amateurs are connected via FIDO. At present, people from SADEYA, GEA, and ASTER are looking to have our own e-mail node, as there are some problems with sending e-mail through NEXUS (We receive mail, but we cannot send it). We would also like to try packet radio. If you are interested in communicating with any Spanish amateur associations, the following is a list of some of the major groups with their regular mail and network address: SADEYA, Sociedad Astronomica de Espana y America Av. Diagonal, 377 2on 08008 Barcelona sadeya@nexus.nsi.es ASTER, Agrupacio Astronomica de Barcelona Passeig de Gracia, 71 atic 08008 Barcelona aster@nexus.nsi.es Agrupacio Astronomica de Sabadell C/Font, 1 1er. 08201 Sabadell (Barcelona) GEA (Grup d'Estudis Astronomics) Ap. Correus 9481 08080 Barcelona gea@nexus.nsi.es (To be implemented soon) Sociedad Malaguena de Astronomia Ap. Correos 6072 29080 Malaga jmartin@nexus.nsi.es Associacio Valenciana d'Astronomia Apt. Correos 2069 46080 Valencia fabregat@evalvx.decnet.cern.ch (Juan Fabregat was AVA President) Agrupacion Astronomica de Madrid Ap. Correos 1039 28080 Madrid Aranzadi Zientzi Elkartea Plaza Ignacio Zuloaga (Museo) 20003 Donosti (San Sebastian) Agrupacion Astronomica Palmera Ap. Correos 449 38780 S.C. de la Palma Agrupacion Astronomica de Tenerife Ap. Correos 10644 38080 S.C. de Tenerife I would like to thank EJASA Editor Larry Klaes for "translating" my original article into readable English and for his general advice. Footnotes: 1 - Comas i Sola discovered planetoids 925, 945, and 956. He also rediscovered planetoids 629, 1102, 1117, 1136, 1188, 1927AA (Sadeya), 1929WG, and 1929XA. 2 - Periodic comet Comas Sola (1926f) was discovered on November 4, 1926. The comet has an orbital period of 8.54 years. 3 - This discovery was made in 1920 and reported in ASTRONOMISCHE NACHRICHTEN, Number 4290. 4 - See the April, 1982 article "Titan" in SCIENTIFIC AMERICAN by Tobias Owen. 5 - The Sociedad Flammarion association was founded in 1881 in Jaen, but dissolved soon after. ASTER has a telescope that is reputed to have been donated by a Sociedad Flammarion member which once belonged to the French astronomer Nicolas Camille Flammarion (1842-1925). Like Josep Comas i Sola, Flammarion was an astronomy popularizer. 6 - IAU Circular 4815, July 19, 1989. 7 - The European Asteroidal Occultations Network (EAON) can be contacted through Mr. Roland Boninsegna, Rue de Mariembourg, 35 B 6381 Dourbes, Belgium. About the Author - Jordi Iparraguirre is a computer science student at "Universitat Autonoma de Barcelona" in Catalonia. Jordi has been the librarian of ASTER (Agrupacio Astronomica de Barcelona) since 1986. As an amateur astronomer, Jordi is encouraging e-mail communication among Spanish amateurs and moderates the public astronomy forum on NEXUS. He takes part in summer meetings organized by J. M. Gomez (GEA, IAPPP Spanish wing). Jordi's professional interests include space probes and unmanned intelligent rovers as a means of exploring our solar system. He would very much like to take doctorate courses on these new planetary machines. If you would like to contact Jordi: E-mail: ipa@nexus.nsi.es (Always, I hope!) di4007@ebccuab1.bitnet (Expires in September of 1990) Regular mail: See the ASTER address above. THE COSMIC DISTANCE SCALE by Eric Greene The history of astronomy is the history of humanity's discovery of the scale of the Universe. The astronomers of ancient Greece made the first scientific attempts at determining the size of our planet Earth and the Universe within which we exist. It was far easier for the Greeks to measure Earth accurately than the entire Universe. This is not surprising: Over two thousand years later we are still coming to grips with understanding a cosmos that is far vaster than the human mind can even begin to comprehend. Before discussing the cosmic distance scale as we understand it today, it is very important to comprehend the idea of parallax. Parallax is essentially the direct trigonometric measurement of distance which can easily be demonstrated: Hold your index finger up against a distant background and look at it while alternately opening and closing each eye. Your finger will appear to move against the background due to binocular vision, the different angle of vision for each eye. If you measure the distance between your eyes and the amount of movement of your finger, it is quite simple to calculate the distance to your finger. Obviously the accuracy of this method is determined by the baseline of the measurements. Human eyes are a few centimeters apart. This method will work out to a distance of twenty-seven meters (thirty yards) or so: You can experiment with this by using objects farther away than your finger and distant backgrounds. Objects more distant will cause too small a "parallactic displacement" to be discernible with the unaided eye. Extending the observational baseline by separating the eyes is a difficult and painful propo- sition at best. The same effect can be had by using two observers making the same measurement on the same object at the same time. This method was used by early astronomers to calculate a fair approximation of the distance from Earth to the Moon, but the unaided eye measurements were not accurate enough to measure anything more distant in space. Early telescopes were very primitive affairs with generally unstable mounts and inaccurate micrometers used for quantitative measurements. The problem of knowing the distance to the stars remained unsolved for over two hundred years after the telescope was put into astronomical use. Since the accuracy of the parallax method depends upon the length of the baseline, the question of the longest baseline available became very important. It is possible to view a star just after the Sun "sets" and, depending on the time of year, see it again just before Sun "rise". Earth has rotated 180 degrees during this time, placing the observer on the other side of Earth (in reference to an outside observer, since the original observer is in the same geographic location). The observer is working with a baseline equal to the diameter of Earth - about 12,800 kilometers (eight thousand miles). Even this baseline is not long enough to detect any parallax in the stars. The same observer can make observations of the same star six months apart. During these six months, Earth has moved from one side of its orbit around the Sun to the other. Since Earth circles the Sun at a distance of approximately 150 million kilometers (93 million miles), the diameter of the orbit is 298 million kilometers (186 million miles). Making observations every six months means working with a baseline of 298 million kilometers (186 million miles). With this technique, the German astronomer Friedrich Wilhelm Bessel (1784-1846) was able to detect the first stellar parallax in 1838. Bessel's subject was the orange (spectral type K) star 61 Cygni in the constellation of Cygnus the Swan. The star was seen to move slightly against the background of dimmer and more distant stars, thus the measurement of this motion could easily be converted into kilometers. The distance from Earth to 61 Cygni was calculated by Bessel to be over 96 trillion kilometers (sixty trillion miles), or about ten light years (the distance has since been refined to 11.2 light years). Attempts at measuring the distances to other stars proved unsuccessful, indicating that these suns must reside at far greater distances than 61 Cygni. The Universe was becoming a much larger place than ever dreamed of before. One of the unusual properties of the Universe (from the average human standpoint) is that we never see the Universe as it is, but only as it was. Light travels at approximately 300,000 kilometers each second (186,000 miles each second). Incredibly swift though this velocity is, it still takes light a measurable period of time to cross astronomical distances. Light requires about eight minutes to cross the 150 million kilometers (93 million miles) between the Sun and Earth, making our star about eight light minutes from our planet. Consequently, we do not see the Sun as it appears in the present, but only eight minutes in the past. Similarly, the light leaving the Sun at present will not arrive at Earth for yet another eight minutes. This relationship between time and distance is one of the most fundamental concepts in astronomy. It is impressed upon us with one of the most basic and essential units of astronomical measurement: The light year. One light year is the distance traveled by light in the course of one Earth year - roughly ten trillion kilometers (six trillion miles). It became much more convenient to talk of the distance to 61 Cygni as 11.2 light years, rather than using trillions of kilometers. Yet this star is one of the closest to Earth; when speaking of the distances to other galaxies, we need to talk of hundreds of millions of trillions of kilometers. Using light years makes things simpler. Another unit of distance finding increased favor in astronomy is the parsec (pc). This measure is defined by parallax. If an object is at a distance of one parsec (3.26 light years), then it will exhibit a parallactic displacement of one arcsecond over a three-month period. At even greater distances, measurement is often quoted in megaparsecs. One megaparsec equals 3.26 million light years and reflects the average distance between galaxies. The most distant galaxies from us are thousands of megaparsecs away. The Universe has become ever larger. Next comes the problems of determining distance once moved far out enough that direct measurement of parallax becomes impossible. We will discover that distance scales become quite vague beyond this distance. One of the astronomer's favorite pastimes is changing the distances to the galaxies. The implications to this are interesting, since time and distance are so closely linked. If an astronomer places the most distant galaxies at ten billion light years and if the galaxies were formed shortly after the creation of the Universe, then the Universe is somewhat older than ten billion years. If the most distant galaxies are placed at twenty billion light years, the age of the Universe must also double to allow sufficient time for the light from those objects to reach us. The distance scale has a profound effect on our concepts concerning the age and formation of the Universe. With continually refined techniques and improved telescopes, it is possible to measure parallax out to distances of over one hundred light years with fair reliability. Once we reach a distance of three hundred light years, the margin for error exceeds the measurement and parallax ceases to be a useful means of determining distance. While three hundred light years is roughly three quadrillion kilometers (1.8 quadrillion miles), this is still right on our doorstep as far as celestial distances go. Astronomers desired the means to determine the distances to the far reaches of our Milky Way Galaxy and the rest of the Universe. A new method of measurement was needed, but no one appeared to have an idea on how to approach the problem. To the casual observer in ancient times, the night time sky was a perfect, changeless place. The eternal stars seemed never to alter position or brightness. The planets, comets, and other phenomena that seemed to change the appearance of the sky were not considered to be parts of the celestial sphere; the stars themselves were unchanging for all times. Arabian astronomers during the European Middle Ages were astute observers of the sky. They noticed that several stars seemed to change brightness. They recorded their amazement at this fact by the names given to these stars: Algol, in the constellation of Perseus, translates to the Demon and is the basis for our word "ghoul". Mira, in the constellation of Cetus the Whale, translates as "wonderful". These stars changed brightness over periods of time - a matter of days for Algol and months for Mira - and these stars became the first of a large group of stars known as variables. Later research showed that some variables, such as Algol, were binary stars in which the dimmer companion occasionally blocks the light of the brighter star from our viewpoint on Earth. Others, such as Mira, varied because of actual changes in the intrinsic brightness of the star itself. The first type of star is known as an eclipsing binary, while the second type is broken into many different categories, such as recurrent nova, dwarf nova, Cepheid variable, RR Lyra, and so forth. We shall concentrate on the Cepheid variables. Variable stars are characterized by their light curve. This curve is a simple graph of the star's brightness on a time scale showing the period of brightness change of the star. Cepheid variables have a characteristic light curve with a fast rise to maximum brightness, followed by a slow decline to minimum magnitude. In 1912, the American astronomer Henrietta Leavitt was studying Cepheid variables in the Small Magellanic Cloud (a companion galaxy to the Milky Way visible from the Southern Hemisphere). Astronomers generally prefer to observe objects in clusters and nearby galaxies, since they can consider all the objects they view as being at the same distance - just as someone in New York City would consider all the people living in London to be the same distance away. Any brightness differences are assumed to be real intrinsic differences, rather than differences caused by distance alone. Leavitt noticed a correlation between the brightness of a Cepheid variable and its period. Her observations were later formulated into the famous Cepheid Period- Luminosity Law by Harlow Shapley in 1917. The law states there is a direct relationship between the period of a Cepheid and its absolute (internal) brightness. Since Cepheid variables are fairly common stars, there are several within the three hundred light year range of direct distance measurement. It therefore became possible to work out their absolute magnitudes. Once these were determined, the Cepheids became a tape measure for finding vast distances quite easily. Measure the light curve of the variable and a simple table tells what its absolute magnitude is. Once you know how bright it actually is, the difference between perceived brightness (dimmed by distance) and actual brightness tells the distance. Since Cepheids are among the more luminous stars, this ruler became useful for measuring the distances of the galaxies that can be resolved into individual stars in large telescopes. In the 1940s, Walter Baade was able to make out Cepheids in the Andromeda Galaxy and determined that this galaxy was at a distance of 2.1 million light years - our next door neighbor, as far as galaxies go. New telescopes and observing techniques allow observing Cepheids out to distances past twenty million light years. Beyond this distance, even the greatest telescopes are unable to resolve individual stars, requiring other techniques for intergalactic distance measurement. These techniques, reaching beyond the nearby galaxies out to the edges of the Universe, will form a later article. Recommended reading: Dickinson, Terence, THE UNIVERSE...AND BEYOND, Camden House Publishing, Ltd., Camden East, Ontario, Canada, 1986 Ferris, Timothy, COMING OF AGE IN THE MILKY WAY, William Morrow and Co., Inc., New York, 1988 Hartmann, William K., and Ron Miller, CYCLES OF FIRE, Workman Publishing, New York, 1987 McAleer, Neil, THE MIND-BOGGLING UNIVERSE, Doubleday & Co., Inc., Garden City, New York, 1987 Moore, Patrick, ASTRONOMERS' STARS, W. W. Norton & Company, New York, 1989 Whitney, Charles A., THE DISCOVERY OF OUR GALAXY, Alfred A. Knopf, Inc., New York, 1971 About the Author - Eric Greene, ASA Observing Coordinator, is an active and avid amateur with a talent for astronomical education and an interest in presenting astronomy comprehensively to all levels of interest in the field. MILTON UPDEGRAFF, ASTRONOMER by Darwin Christy, Buffalo Astronomical Association Milton Updegraff, a little-known American astronomer, was born on February 20, 1861, in Decorah, Iowa. After graduating from the University of Wisconsin in 1884, Updegraff was employed as an aid on the United States Coast and Geodetic Survey until 1887. He became an Astronomo Segundo (assistant) Observatorio Nacional in Cordoba, Argentina, from 1887 to 1890. Updegraff taught astronomy at the University of Missouri from 1890 to 1899, after which he was selected for the position of Professor of Mathematics for the United States Navy (USN). Updegraff subsequently became an astronomer in the U.S. Naval Observatory until 1902. While there, he was placed in charge of the U.S. Naval Observatory's May 1900 Eclipse Party at Barnesville and Griffin in Georgia. In 1902, Updegraff accepted the appointment as Instructor in the U.S. Naval Academy, which he held until 1907. Being an experienced astronomer, Updegraff was designated as director of the Nautical Almanac in Washington from 1907 to 1910. During the last two years of his time as director, Updegraff was also assigned to the fifteen-centimeter (six-inch) transit circle of the Naval Academy. A transit circle is a special telescope that only moves north-south, fixed in hour-angle (that is, it sweeps the meridian). When a star passes through its crosshairs, a timing measure can measure the star's right ascension very accurately. Also, by examining stars of known right ascension, the local time can be ascertained very accurately. This method was used to keep inaccurate clocks properly set until atomic clocks were developed. Now it is used to measure Earth's variation in its rate of rotation. From 1913 to 1915, Updegraff headed the geodetic and other scientific work in the American Survey of Samoa. From 1915 to 1917, he was stationed at the Mare Island Navy Yard, at the north end of San Francisco Bay, California, and was also a meteorological observer in Arizona, retiring in July of 1920 with the rank of Commander. He was elector of the New York University Hall of Fame in 1925, 1930, and 1935, and also served as a Fellow of the American Association for the Advancement of Science (AAAS). It is difficult to find biographical material on Updegraff, as his contributions to astronomy were relatively minimal. Updegraff did, however, hold a number of significant positions as an astronomer and teacher of astronomy and mathematics, and wrote several articles on professional subjects. Living at his home in Prescott, Arizona in his later years, Updegraff passed away on September 12, 1938, at the age of seventy-seven years. From the Editor: No known history has been written describing the May 1900 Eclipse Party conducted in Georgia by the United States Naval Observatory and Milton Updegraff. A worthwhile research pro- ject for any interested readers would be to request records from the Naval Observatory pertaining to Professor Updegraff and the Georgia Expedition, in order to prepare a report on this virtually unknown and important event in Georgia's past. In 1900, the science and engineering of photography, solar physics, and portable observing instrumentation were in rapid development. An account of the eclipse, therefore, would encapsulate the state of a large part of astronomy at that time. If interested, please contact the Astronomical Society of the Atlantic at one of the addresses listed in the ASA Membership section of this issue. We can then direct you to some information sources at the Naval Observatory as a starting point. About the Author - Darwin Christy is Newsletter Editor of the "Spectrum, the newsletter of the Buffalo Astronomical Association in Buffalo, New York and an active amateur astronomer with an interest in the history of astronomy. THE ELECTRONIC JOURNAL OF THE ASTRONOMICAL SOCIETY OF THE ATLANTIC April 1990 - Vol. 1, No. 9 Copyright (c) 1990 - ASA -- Donald J. Barry (404) 651-2932 | don%chara@gatech.edu Center for High Angular Resolution Astronomy | President, Astronomical Georgia State University, Atlanta, GA 30303 | Society of the Atlantic ------------------------------ End of SPACE Digest V11 #216 *******************