|simple theodolite: surveying instrument for measuring horizontal angles, see article on the theodolite.
|sinical quadrant: a quarter of a circle with a scale of degrees at its circumference which carries a pattern of criss-crossing vertical and horizontal lines. The ratio of the length of a given line to the quadrant's radius gives the sine or cosine of the corresponding angle.
|solar time: time measured directly from the position of the sun, see article on the sundial.
|solstice: either of two points on the ecliptic where the sun achieves its maximum declination. The term also refers to the two dates when the sun reaches this position in its annual cycle. The winter solstice corresponds to the shortest day, the summer solstice to the longest. Near these points the sun's declination changes only slowly, hence the etymological meaning of solstice as 'standing sun'.
|star pointer: point marking the position of a star, see article on the astrolabe.
|string gnomon: the part of a sundial which casts the shadow, where this part is in the form of a taut string.
|sun and moon dial: sundial that can also tell the time from the shadow cast by the moon, see article on the sundial.
|sundial: instrument of many different forms for finding the time from the position of the sun, usually by measuring the position of a shadow, see article on the sundial.
|sundial and dividers: a compound instrument combining the functions of both a sundial and dividers.
|surveying and gunnery instrument: compound instrument combining functions required in the closely-associated fields of surveying and gunnery, such as measuring bearings and finding ranges.