This laboratory requires your laptop. We will be following one of the Contemporary Laboratory Exercises in Astronomy (CLEA) produced in the Physics Department at Gettysburg College. You'll get some practice today classifying stars according to the so-called Harvard spectral classification scheme. We'll use the CLEA exercise on Stellar Spectra. Download and install the file "SpecLab.EXE" from that site. It is not necessary to download the other files posted there, but you are welcome to do so.

If you want to work in pairs, that is fine. Please, however, no more than two people to a group.

Dowload Part III of the Spectral Classification Student Manual. This is what you'll work on and hand in today. In particular, you will answer the several questions in the documentation, and fill out the table on Page 13.

Answer the following questions, printed in bold type in the documentation:

• Section 2, questions a, b, and c.
• Section 5, questions a, b, and c.
• Section 7.
• Section 9. Also, identify the line located between the two lowest hydrogen lines, that disappears past spectral class B6. Explain why it disappears for the higher spectral types.
• Section 10.
• Section 11: Here you can use what you learned above to classify a list of stars.

You don't have to list all the reasons on the data table (they are likely to get rather monotonous) but if you see something strange, you should make a note of it.