Notes from the Gettysburg CLEA Workshop

Michael Richmond
June 8, 2003


It may be useful to look at the syllabus to a course on Observational Astronomy I taught at RIT.

Basic CCD processing: cleaning a raw image

You can find an overview and some links to more detailed information by going to

Some notes on parallax measurements of asteroids

Some notes on photometry

Beyond the "Large Scale Structure" exercise

In the CLEA Large Scale Structure exercise, you and your students map a small portion of the local universe with several hundred galaxies. You end up with a picture like this:

It seems clear that galaxies are clumped together, rather than filling space uniformly. But there isn't a lot to see. Note that the most distant galaxy has a velocity of about 15,000 km/sec, which corresponds to a redshift of about 0.05.

In recent years, many astronomers have spent a great deal of time and effort to measure the spectra (and so relative distances) of LOTS of galaxies. Two of the main surveys are

Recent maps of the universe show many more galaxies over a much larger volume: this map from the 2dF goes out to a redshift of about 0.30, about six times deeper than the CfA survey. That means it includes a volume about 6^3 = 216 times larger.