For even finer gradation in the spectral sequence, each category in
this classification can be
subdivided into 10 subclasses using numbers from 0 to 9. Thus, for example, the
classes O and B
can be subdivided into the finer classes O0, O1, O2, O3, ... O9, B0, B1, B2,
... B9.
Here are some postscript files of
example spectra
for
each of these spectral classes.
