Measure Spectral Characteristics of ESI

This test will calibrate the number of counts/second a star of given
brightness provides on the LRIS detector, as well as a measurement of
the total system throughput.

It will also provide a measurement of the run of the spectrum across the 
image.

It can be run in either low- or high-res mode, although the standard
stars selected may be different.

1) Select a spectrophotometric standard from the starlist:

0000spectraphoto.stds

or possibly one of a set of stars provided by the engineering team.

2) Center the standard star on the slit and take a well-exposed spectrum.