We will start with the solar spectrum. Use the small mirror on an adjustable stand to direct skylight from the classroom windows into the entrance slit. The mirror will be at about 45 degrees to the line from the slit and tipped upward slightly so that a fuzzy patch of light is on the entrance aperture of the spectrograph. It will help to use a 3x5 file card to check where the light is going. Use the 100 second exposure time and take an image CCD exposure. When the exposure is finished the image will be displayed automatically in the ds9 window. You may not be able to see much at this point, since the range of data in the image and the range of intensity levels on the display will not be well matched. Notice that as you run the cursor around over the image without pressing a mouse button the coordinates of each pixel will be displayed, along with the signal level at that point. Typical values should be around 10000 ADU if the mirror is properly adjusted and it is not raining outside.
Save this exposure by using the File -> Save Frame As Fits menu. Give the file a
distinctive name. You will find the files you create now in the ``spectra'' directory
later.
You will also need an exposure when no light is present. This ``dark'' frame will be subtracted from the image exposure to yield a measurement of the signal from light alone. Take a dark exposure with the same exposure time, 100 seconds, that you used for the solar spectrum. Save the new frame as a fits file with a new name.