We derive physical parameters of galaxies from their observed spectra using
MOPED, the optimized data compression algorithm of Heavens, Jimenez & Laha
v. Here we concentrate on parametrizing galaxy properties, and apply the me
thod to the NGC galaxies in Kennicutt's spectral atlas. We focus on derivin
g the star formation history, metallicity and dust content of galaxies. The
method is very fast, taking a few seconds of CPU time to estimate similar
to 17 parameters, and is therefore specially suited to studying large data
sets, such as the Anglo-Australian two-degree-field (2dF) galaxy survey and
the Sloan Digital Sky Survey (SDSS). Without the power of MOPED, the recov
ery of star formation histories in these surveys would be impractical. In K
ennicutt's atlas, we find that for the spheroidals a small recent burst of
star formation is required to provide the best fit to the spectrum. There i
s clearly a need for theoretical stellar atmospheric models with spectral r
esolution better than I A if we are to extract all the rich information tha
t large redshift surveys contain in their galaxy spectra.