Essentially, this instrument is a celestial planisphere which can be rotated over a plate on which there is a network of azimuths (bearings) and almacantars (altitudes).
Esifunekayo isilinganisi sesibhaka-bhaka esizolileyo esinokujikeleza ngaphaya kwepleyiti apho kukho uqhngamshelwano lweazimuths (ukuthwala) nealmakhathari (kumphakama).