  We update the online SpectroWeb database of spectral standard reference stars
with 1178 oscillator strength values of atomic absorption lines observed in the
optical spectrum of the Sun and Procyon (Alpha CMi A). The updated line
oscillator strengths are measured with best fits to the disk-integrated
KPNO-FTS spectrum of the Sun observed between 4000 A and 6800 A using
state-of-the-art detailed spectral synthesis calculations. A subset of 660 line
oscillator strengths is validated with synthetic spectrum calculations of
Procyon observed with ESO-UVES between 4700 A and 6800 A. The new
log(gf)-values in SpectroWeb are improved over the values offered in the online
Vienna Atomic Line Database (VALD). We find for neutral iron-group elements,
such as Fe I, Ni I, Cr I, and Ti I, a statistically significant over-estimation
of the VALD log(gf)-values for weak absorption lines with normalized central
line depths below 15 %. For abundant lighter elements (e.g. Mg I and Ca I) this
trend is statistically not significantly detectable, with the exception of Si I
for which the log(gf)-values of 60 weak and medium-strong lines are
substantially decreased to best fit the observed spectra. The newly measured
log(gf)-values are available in the SpectroWeb database at
http://spectra.freeshell.org which interactively displays the observed and
computed stellar spectra, together with corresponding atomic line data.
