  The Sun may copiously produce hypothetical light particles such as axions or
dark photons, a scenario which can be experimentally probed with so-called
helioscopes. Here we investigate the impact of the angular and spectral
distribution of solar dark photons on the sensitivity of such instruments. For
the first time we evaluate this spectral and angular dependence of the dark
photon flux over the whole mass range and apply this information to existing
data from the Hinode Solar X-Ray Telescope. Specifically we use calibration
images for a classical helioscope analysis as well as data from a solar eclipse
providing sensitivity to exceptionally large oscillation lengths. We
demonstrate that exploiting the signal features can boost the constraints by
more than one order of magnitude in terms of the mixing parameter compared to a
naive counting experiment.
