|
nautical circle: generic term for a circular mathematical instrument of use in navigation, but likely to carry a range of mathematical and astronomical scales.
|
nautical hemisphere: a combination of graduated arcs and circles used for navigational calculations, see article on the nautical hemisphere.
|
navicula dial: type of altitude dial in the shape of a ship.
|
nocturnal: instrument for finding the time at night from the orientation of the stars, see article on the nocturnal.
|
nocturnal and quadrant: compound instrument which combines both the functions of a nocturnal and quadrant, usually on two different sides of the same instrument, with equal importance given to each.
|
nocturnal and sundial: compound instrument which combines both the functions of a nocturnal and sundial, usually on two different sides of the same instrument, with equal importance given to each.
|
nonius: a way of subdividing a quadrant of a circle to provide fine discrimination of parts of degrees, comparable in purpose to the later vernier scale. The name comes from the latinized surname of the 16th-century Portuguese mathematician Pedro Nu?ez.
|
Nuremberg hours: system of hour reckoning, see article on time and date.
|
octant: the eighth part of a circle or an instrument measuring up to 45 degrees.
|
old quadrant: type of horary quadrant, see article on the quadrant.
|
opposition: two planets 180? from each other in the ecliptic are said to be in opposition. This relative position had important astrological significance.
|
ordinary hours: system of hour reckoning, see article on time and date.
|
orthographic planisphere: flat map produced by orthographic projection.
|
pedometer: device worn by a walker to measure distance by counting paces.
|
pendant sundial: a form of sundial suspended by a cord and possibly hung around the neck.
|
perpetual calendar: calendar covering a number of years, see article on time and date.
|
phase of the moon: the changing appearance of the moon throughout its approximately monthly cycle, from the thin crescent of new moon to the complete circle of full moon and back again.
|
pillar dial: type of altitude dial, see article on the sundial.
|
pin gnomon: the part of a sundial which casts the shadow, where this part is in the form of a pin.
|
plane table: type of surveying instrument, see article on the plane table.
|
plane table alidade: an alidade specially adapted for use with a plane table.
|