Sky-Polarimetric Viking Navigation

摘要: It is a widely discussed and regularly cited theory that Viking navigators might have been able to locate the position of sun occluded by clouds or below horizon with mysterious birefringent dichroic crystal, sunstone, on basis pattern skylight polarisation. In this chapter we describe steps experimentally tested efficiency sky-polarimetric navigation method, show modern instruments operate in similar principle. We investigate atmospheric optical prerequisites navigation, looking for ideal weather conditions, under which sunstones could be used navigational task. also discuss other hypothesised instruments, like board compass twilight board. Finally, consider Medieval Norse sailing routes some alternative cues, help during long-time marine voyage seafarers.