Astronomical quadrant
Cuadrante astronómico (quadrans vetus y cuadrante horario)
- Date
- c. 850 · confidence low
- Place
- Baghdad / Egypt (sine quadrant), Montpellier (quadrans novus, 1288)
- Credited to
- al-Khwarizmi (sine quadrant); Jacob ben Machir (quadrans novus)
- People
- 👤 Al-Juarismi750–846
- Field
- Knowledge & symbols
What it is
A graduated quarter-circle with a plumb line and sights, used to measure the altitude of celestial bodies and solve trigonometric problems graphically. Cheaper and simpler than the astrolabe.
What it led to
- the basic instrument of the Portuguese navigator (measuring the altitude of the Pole Star)
- the determination of latitude during Atlantic exploration
- the teaching of astronomy in universities
Built on
- Sundial / shadow clockc. 1500 BCE
- Armillary spherec. 255 BCE
- Islamic astronomy and the Zij tablesc. 830
- Islamic planispheric astrolabec. 900
- Trigonometry as a disciplinec. 980
- Islamic planispheric astrolabe
- Trigonometry as a discipline