|
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.
|
