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M. L. West (Montclair State University)
The Sunspotter, a wooden triangular folded telescope, is available from Learning Technologies, Inc. and is a safe and efficient way for many people to view the sun's image at once. Each observation takes about a minute, but different opportunities for analysis arise when data are accumulated over various time scales. Each set of observations can be understood with a simple model (usually linear) and then analyzed further with the model refined in some way. This is a great opportunity to impress on students how the scientific process works.
The most straight-forward activity is to determine the rotation period of the sun from daily tracings of sunspots for a week. De-projecting in longitude gives a more accurate value for the period than a linear plot.
The Earth's rotation period can be determined with a two-minute observation. A circle the size of the sun's image is provided, and students use a stopwatch to time the passage of the image until it exits the circle. Using the tabulated solar diameter for the date of the observation gives a value much closer to 24 hours than assuming the sun is exactly half a degree in diameter. Conversely, Sunspotter timings over a period of months can show the changing distance of the Earth from the sun.
One student counted the sunspots visible in this small telescope for two months and found that his tallies correlated moderately well with NOAA's numbers, especially when a weighting was used for sunspot groups.
The Christmas partial eclipse of 2000 was fun to view and photograph with a Sunspotter. Setting it on the frozen ground kept it out of the wind, and the image was much steadier than in a telescope on a tripod. Even toddlers could enjoy the show.
If you would like more information about this abstract, please follow the link to http://www.csam.montclair.edu/~west. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.
The author(s) of this abstract have provided an email address for comments about the abstract: west@pegasus.montclair.edu