Pembroke college, Cambridge
“The principal dial furniture consists of hour-lines marked
from 6 am to 4 pm and three constant-declination curves (a pair of hyperbolic arcs for the two solstices and a straight line, called the equinoctial line, for the equinoxes).
This sundial has a gnomon and a nodus, both made of stainless steel. Time is determined by noting where the shadow of the gnomon falls among the hour-lines and the declination of the sun can be estimated by noting where the shadow of the nodus falls among the constant-declination curves“ cl.cam
