Figure 17. Luksch disk, made by Joseph Luksch about 1880 and used in that year
aboard the HERTA, the yacht of Prince John II of Liechstenstein. It was provided
with five interchangeable 36-cm reflecting plates of different metals, some
painted. Afterwards, Luksch used polished white iron disks and white painted
disks of 45 cm diameter on the POLA.