Today's partial solar eclipse happened from 11:44 to 13:55 local time, so we combined observing the eclipse with a lunch-picnic for the whole lab.
One telescope with a 25mm positive lens at the eye-piece projected an image of the sun into a cardboard box. Another was used with a tracking mount and an OD=5 solar filter for visual observations and photography.
It was cloudy before the eclipse and rainy in the afternoon so we were lucky with the weather!
Variations on the same theme:
I got an OD=5 solar filter for my 80 mm refractor and took a first look at the sun this afternoon. Two sunspots are clearly visible. The large spot at 3 o'clock is dirt on the camera sensor. The apparent rotation period is supposed to be around 28 days, so by taking a picture each day it should be possible to make a time-lapse movie.
To really see structure in the sun requires a very narrow (~0.7 Ã…ngstrÃ¶m) bandpass filter centered around the H-alpha emission line at 656.28 nm. Unfortunately these range from expensive to very expensive...