Hidden Photons are presumably generated in vast numbers in the Sun's interior and atmosphere. In free space HPs can convert back into real photons through a mechanism analogous to neutrino flavor oscillations. The HP- hν resonant coupling is weak but finite. It can locally be suppressed by the refractive index of the medium in the oscillation regime, such that a telescope operation in a vacuum is called for. Regenerated electromagnetic photons propagate along the same trajectories as their HP progenitors, suggesting the use of an imaging astronomical telescope. Since secondary HP-photons emerging from the vacuum between the Sun and the Earth cannot be distinguished from the overwhelming solar flux, the HP-photon vacuum telescope must also be totally shielded from parasitic solar and ambient light.
During the SHIPS experiment, the Sun is observed almost continuously in the 'light' of the HPs with dedicated helioscopes: adapted astronomical telescopes employing imaging optics and low-flux detectors in a vacuum chamber to achieve high sensitivity, contrast and spatial resolution.
SHIPS is an offspring of the ongoing ALPS (“Any Light Particle Search“) projects at DESY. Unlike the laboratory experiments ALPS and ALPS II, SHIPS does not involve magnetic fields.
The SHIPS helioscopes are located at the Bergedorf site.