![]() ![]() The online catalog will show the position, motion, brightness and colors of more than 100 million objects in the Milky Way Galaxy. We will get better results, but it’s not the optimum detector for this project.”Ī compilation of the data, which van Altena said was the best available of the southern sky, will be made available online early this summer, accompanied by a written description of the project in the Astronomical Journal. “The new detectors are 100 times faster, but because they are so small, in the end, you have the problem of having to combine all the individual images,” van Altena said. ![]() ![]() ![]() Although the project’s CCD is the largest in Argentina, at 2 ½-by-2 ½ inches, it takes 50 to 60 images from the CCD to equal one photographic plate. The team also lost time adjusting to the new CCD and dealing with the added complications that came with its small size. But when Kodak stopped making the 17-by-17–inch photographic plates used to capture the images of the stars in the mid-1990s, the project struggled to raise the money from the National Science Foundation to purchase the new technology - charge-coupled devices, or CCDs, the chips used in digital cameras to store pictures - they needed to continue photographing the stars. Still, the research should have been finished a decade ago, van Altena said. “But some of the important astronomical research, such as measurements of proper motions of stars in our Milky Way Galaxy led by Professor van Altena, do require a lifelong effort.” “It has become extremely unusual to conduct research on one project for 40 years,” astronomy professor Daisuke Nagai said. The resulting measure of the angular motion of the stars was measured in milliseconds of arcs per year - which is why the project took more than four decades.īut though the nature of the research required that the project be conducted over several decades, van Altena and his colleagues in the Department of Astronomy agreed that such a lengthy project is rare in the world of astronomy. Girard said the motion of the stars was found by comparing older images of the star fields with more recent ones - measuring the position of a star relative to other stars and to background galaxies and quasars. Over the next three decades, van Altena’s team, which included an average of six to 10 people at a time, used the observatory’s astrograph to photograph the southern sky. Cesco Observatory) in Argentina with an agreement between Yale and the National University of San Juan, in which the UNSJ agreed to pay the support staff salaries and Yale agreed to pay capital costs and the observer’s salary.Īfter the death of the first project director, Dirk Brouwer, in 1966, Yale astronomer Adriaan Wesselink led the team until van Altena was recruited in 1974. Research for the SPM project began in 1965 at the El Leoncito Observatory (later the Dr. “Unfortunately, this field of study, astrometry, has become less well-supported - in this country at least - at a time when it is becoming more relevant than ever.” “Bill van Altena has dedicated his entire career to doing what many consider a not-so-glamorous but fundamentally important job,” said Terry Girard, a research scientist who has worked with van Altena on the Southern Proper Motion project for the past 23 years. But the project’s completion comes at a time when interest in astrometry - the science of measuring the position and motion of stars - is rapidly dwindling in the United States. The Yale/San Juan Southern Proper Motion project, led by William van Altena, a professor emeritus of astronomy, has cataloged the proper motion of the celestial objects that light up the sky of the southern hemisphere. After 44 years of research at an observatory in the foothills of the Andes, astronomers are nearing the end of a monumental undertaking: tracking the motion of 100 million stars. ![]()
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