The Sun and Solar Cycles

xraysun.jpgSunspots were first observed by Galileo. In addition to counting sunspots and noting where along the Sun's latitude they are located, one can also use them to observe the Sun's rotation. The number of sunspots varies but 1999 and 2000 are near sunspot maximum and many (5-10) should be observable.

This project can be done at the Observatory or by checking out a portable telescope, which has a 3 inch mirror. A screen can be attached to this telescope allowing for a projection of the Sun's image. NEVER LOOK DIRECTLY AT THE SUN THROUGH A TELESCOPE. The projected image is safe, and also convenient for making drawings or taking photographs. Sometimes it helps to shade the screen from direct sunlight.

Use the setup to observe sunspots for a number of days. Note the number, and pattern, and see if the sunsopts move. Estimate the Sun's rotation-how many Earth days correspond to one Solar "day"? Does it vary with ther Sun's latitude? Make drawings (or take a picture) of the sunspots locations and sizes.

Observatory Manager

Joe Piet


Davis Hall Room 703
Normal and Locust Roads
DeKalb, IL 60115
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