  We explore how the Peccei-Quinn (PQ) axion parameter space can be constrained
by the frequency-dependence dimming of radiation from astrophysical objects. To
do so we perform accurate calculations of photon-axion conversion in the
presence of a variable magnetic field. We propose several tests where the PQ
axion parameter space can be explored with current and future astronomical
surveys: the observed spectra of isolated neutron stars, occultations of
background objects by white dwarfs and neutron stars, the light curves of
eclipsing binaries containing a white dwarf. We find that the lack of dimming
of the light curve of a detached eclipsing white dwarf binary recently
observed, leads to relevant constraints on the photon-axion conversion. Current
surveys designed for Earth-like planet searches are well matched to strengthen
and improve the constraints on the PQ axion using astrophysical objects
radiation dimming.
