Introduction
Calculation and observation activities in astronomy are closely intertwined. Astronomers measure the position of
the Sun to calculate time or vice-versa. Some among them measure the positions of the stars to determine the points
of the Earth. Some also measure the planetary position to predict the future occurrence of celestial phenomena, or to
verify the mathematical model of the celestial movement formula which they created. Observations to gather
empirical data require special instruments, in the same way as calculation requires the aid of calculation tools. When
these two requirements are combined, it becomes an astronomical instrument rich with concepts of geometry,
arithmetic and trigonometry. Among the instruments that meets this purpose are the astrolabe and sine quadrant.
The purpose of this study is to adapt the use of sine quadrant as a solution to solve trigonometric equations, which
are usually performed by using logarithm tables or scientific calculators. This can only be done when mathematical
descriptive elements in the treatise have been transformed into quantitative formulae with specific symbols and
notations.