| has gloss | eng: The sine quadrant (Arabic: Rubul mujayyab, الربع المجيب) was a type of quadrant used by medieval Arabic astronomers. It is also known as a "sinecal quadrant" in the English-speaking world. The instrument could be used to measure celestial angles, to tell time, to find directions, or to determine the apparent positions of any celestial object for any time. The name is derived from the Arabic "rub" meaning a quarter and "mujayyab" meaning marked with sine. It was described, according to King, by Muhammad ibn Mūsā al-Khwārizmī in 9th century Baghdad. |
