  We present a new determination of the solar fluorine abundance together with
abundance measurements of fluorine in two Galactic open clusters. We analyzed a
sunspot spectrum, observed by L. Wallace and W. Livingston with the FTS at the
McMath/Pierce Solar Telescope situated on Kitt Peak and spectra of four giants
in the old cluster M 67 ($\sim$4.5 Gyr) and three giants in the young cluster
NGC 6404 ($\sim$0.5 Gyr), obtained with the CRIRES spectrograph at VLT.
Fluorine was measured through synthesis of the available HF lines. We adopted
the recent set of experimental molecular parameters of HF delivered by the
HITRAN database, and found a new solar fluorine abundance of $A(F) = 4.40\pm
0.25$, in good agreement with the M 67 average fluorine abundance of $A(F) =
4.49\pm 0.20$. The new solar abundance is in a very good agreement with the
meteoritic value. The used modern spectrosynthesis tools, the agreement with
the meteoritic value and with the results in open cluster M67, known to be a
solar analogue, make our solar determination very robust. At the same time, the
fluorine measurement in the above-mentioned open clusters is the first step in
the understanding of its evolution during the last $\sim$10 Gyr in the Galactic
disk. In order to develop this project, a larger sample of open clusters is
required, so that it would allow us to trace the evolution of fluorine as a
function of time and, in turn, to better understand its origin.
