Online help for SPECTIME
If the above wavelength is set to INDEF or blank it is computed from
the blaze peak of the disperser.
Describe the source with the following parameters. The power law index is
only used if the source spectrum is set to F_power or F_power.
Setting the power law index to 0 is equivalent to a flat spectrum
for that particular power law function.
If the value of the
wavelength of the source flux is set to INDEF then the central wavelength
value above is used. The wavelength of the source flux
is ignored for source units = U, B, V, R, I.