Precise timings of second and third contacts, made near the northern and southern limits of the umbral path (i.e. - the graze zones), are of value in determining the diameter of the Sun relative to the Moon at the time of the eclipse. Such measurements are essential to an ongoing project to monitor changes in the solar diameter. Due to the conspicuous nature of the eclipse phenomena and their strong dependence on geographical location, scientifically useful observations can be made with relatively modest equipment. Inexperienced observers are cautioned to use great care in making such observations. The safest timing technique consists of the inspection of a projected image of the rather than direct viewing of the solar disk. The observer's geodetic coordinates are required and can be measured from USGS or other large scale maps. If a map is unavailable, then a detailed description of the observing site should be included which provides information such as distance and directions of the nearest towns/settlements, nearby landmarks, identifiable buildings and road intersections. Alternatively, beacon devices are commercially available (~$500 US) which provide the user's location via global positioning satellites. The method of contact timing should also be described, along with an estimate of the error. The precisional requirements of these observations are +/-0.5 seconds in time, 1" (~30 meters) in latitude and longitude, and +/-20 meters (~60 feet) in elevation. The International Occultation Timing Association (IOTA) coordinates observers world-wide during each eclipse. For more information, contact:
Dr. David W. Dunham/IOTA 7006 Megan Lane Greenbelt, MD 20770-3012 U. S. A.Send reports containing graze observations, eclipse contact and Baily's bead timings, including those made anywhere near or in the path of totality or annularity to:
Dr. Alan D. Fiala Orbital Mechanics Dept. U. S. Naval Observatory 3450 Massachusetts Ave., NW Washington, DC 20392-5420