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Required SoftwareClick Filename to Download
Or Icon to Go to FTP Site,
These are self-extracting files and will install
themselves when you run them on your computer.
|Purpose: To introduce
students to the techniques that astronomers use to measure the rotation
rate of the sun using images of sunspots. To introduce some
of the difficulties of using two-dimensional images to derive three-dimensional
properties of celestial objects.
This exercise enables students to measure the rate of rotation of the sun at various latitudes using an archive of 368 images of the sun obtained over a four month span in 2002 obtained by the GONG project . Because of the high spatial and temporal resolution of the sample, these are the best images to date from which students can determine the solar rotation rate. Software provided enables student to access the GONG images, display them as still images or animations, measure and record the positions of sunspots, plot its heliocentric coordinates versus time, and thus determine the apparent rotation period of the spot. A second archive of an additional 375 images spanning June to August 2002 was made available in November 2003.
A student manual provided for this exercise describes the method
of analysis and the operation of the software. It provides two possible
ways of doing the exercise, a "Discovery Based" procedure which is open-ended,
and a "Step by Step" procedure which leads students through the exercise,
filling in tables and answer sheets as they go.
The downloadable file accessed on this page is a self-installing file which contains 11 images suitable for measurement . It can be used to measure one or two spots, and will give a flavor of the exercise.
The full dataset, with a self-installing program for the software
and the data, is available free of charge by writing Project CLEA, Department
of Physics Gettysburg College, Gettysburg, PA 17325, (email
), or by filling in the request form accessed by the link on this page.
[AVAILABLE FOR WINDOWS ONLY]
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