For detailed survey plane tables of Morinoni and Kraft trademarks has been used, fitted with peep-sight alidade
, first with diopter, later with a telescope.
Their skill at locating fires with alidades
foreshortened fires' lead time, reducing fire severity.
Rotatable around the graduated circle are two alidades
that have small plates mounted at perpendicular angles to their extremities and perforated at the same distance from the plane of rotation.
One of the points that emerges from Hutchins's discussion of (modern) Western and Micronesian navigational methods in chapter two is the extent to which Western navigation has become heavily dependent on technology: alidades
, bearing logs, hoeys, charts, radar, pit swords, chronometers, and fathometers are all specially developed or deployed cognitive artifacts that allow vessels controlled by Western navigators to complete their journeys.
"The Universe in Your Hands" will acquaint visitors with scientific tools, such as alidades
and astrolabes used by astronomers in the Middle Ages.