Congratulations! Now that you've shown you're able to interpret the spectrum for a real binary star system, HT Cassiopeia, and a car's turn signal, let's move on to another binary system, GX301-2, in a different stage of evolution from HT Cas. This is more challenging because you'll be producing the spectrum yourself from the raw data taken by the X-ray telescope on the RXTE satellite.

The process goes like this:

• Download and install the software "College Hera" that manipulates the raw data file.
  (You'll now have this window plus another Hera interface window.)
  The raw data is in the standard form most astronomers use, called Flexible Image Transport System (FITS).

• Learn to use the basic Hera function "File Plot" to produce a plot or graph of the GX301-2 data. This process is called the "data reduction," and it's so important most of astronomers spend much of their time doing it.

• Analyze your light curve to find the period of GX301-2.

• Compare your results to the results of an X-ray scientist.