EXERCISES IN PRACTICAL ASTRONOMY USING PHOTOGRAPHS: With Solutions by M.T.Bruck IOP Publishing Ltd., 335 East 45th Street, New York, NY 10017-3483 QB62.5.B78 533.076 dc20 1990 ISBN 0-7503-0061-2 Contents: 1. The Sun Rotation Sun's period of rotation Area of a sunspot 2. Minor Planets or Asteroids Identification of belt asteroids Distance of belt asteroids 3. Halley's Comet Direction and length of tail Motion in the plane of the sky Disconnection event in ion tail 4. The Milky Way Photographic stellar photometry Star numbers and magnitudes Variation of star density with galactic latitude 5. Stars in Motion Proper motion Radial velocity 6. Open Star Clusters The Pleiades Distance and age of a star cluster 7. Globular Star Clusters Tidal radius of a globular cluster Mass of the cluster 8. Interstellar Extinction The extinction or reddening law Grain density in an interstellar dust cloud 9. A Supernova and Supernova Remnants Light curve of SN 1987A Luminosity of SN 1987A Expansion and distance of the Crab nebula Dimensions and age of the Vela supernova remnant 10. Types of Galaxies Classification of galaxies Classification of members of the Virgo cluster 11. Nearby Galaxies Types of clusters Distance of a cluster of galaxies Dimensions and contents of a cluster Mass of a cluster by the virial theorem Average mass of a cluster member Appendix 1. Astronomical Definitions, Data and Conversions Appendix 2. Magnitudes, Colours and Luminosities Appendix 3. Sources and References Practical work in astronomy at elementary and intermediate levels presents a difficulty for teachers. Unlike laboratory sciences, astronomy does not easily lend itself to bench experiments. Actual telescope observations are usually limited to the Moon and planets. Meaningful observations of stars or galaxies, to match the instruction received in the classroom or from the textbook, are next to impossible. Astronomical photographs supply an answer; they show what celestial objects actually look like, and are at the same time capable of being used to set problems relevant to the course work. In these exercises, prints of first-class original photographs are reproduced. The photographs (except for those of the Sun) are negatives (black images on a clear background), as used by astronomers in their researches, on which objects can be identified and classified, their dimensions measured or their numbers counted. To use the photographs effectively requires only the most basic equipment. Though the methods of study are simple, they are in principle the same as those used by astronomers with their more elaborate resources. Suggested equipment needed: 1. a millimeter ruler (which could be a strip of millimeter graph paper) 2. a compass 3. a protractor for measuring angles 4. a 10x magnifier, if possible with a graticule divided into 0.1 mm 5. sheets of transparent overlay for tracing objects 6. millimeter graph paper 7. a hand calculator (with trig and log functions) 8. the use of a globe EXERCISES IN PRACTICAL ASTRONOMY USING PHOTOGRAPHS: With Solutions, would make an excellent second text for first astronomy courses such as the one Dave Oesper teaches. - S. Wormley