Extraodinary 9th Century Islamic Astronomy

1. Habash al-Hasib al-Marwazi
died after 869 AD
He flourished in Baghdad .
He was a great astronomer, geographer, and mathematician
He described first time Trigonometric ratios: SIN, COS, TAN & COT.
He made observations from 825 to 835, and compiled three astronomical
tables: Habash gives us the first instance of a determination of time by an
altitude (in this case, of the sun); a method which was generally adopted by
Muslim astronomers.
In 830, he seems to have introduced the notion of "shadow," umbra (versa),
equivalent to our tangent in trigonometry, and he compiled a table of such
shadows which seems to be the earliest of its kind.
He also introduced the cotangent, and produced the first tables for it.

2. The Book of Bodies and Distances
Al-Hasib conducted various observations at the Al-Shammisiyyah
observatory in Baghdad and estimated a number of geographic and
astronomical values.
He compiled his results in The Book of Bodies and Distances, in which some of
his results included the following:
Earth
Earth's circumference: 20,160 miles (32,444 km)
Earth's diameter: 6414.54 miles (10323.201 km)
Earth radius: 3207.275 miles (5161.609 km)

3. Moon
Moon's diameter: 1886.8 miles (3036.5 km)
Moon's circumference: 5927.025 miles (9538.622 km)
Radius of closest distance of Moon: 215,208;9,9 (sexagesimal) miles
Half-circumference of closest distance of Moon: 676,368;28,45,25,43
(sexagesimal) miles
Radius of furthest distance of Moon: 205,800;8,45 (sexagesimal) miles
Diameter of furthest distance of Moon: 411,600.216 miles (662,406.338 km)
Circumference of furthest distance of Moon: 1,293,600.916 miles
(2,081,848.873 km)

4. Sun
Sun's diameter: 35,280;1,30 miles (56,777.6966 km)
Sun's circumference: 110,880;4,43 miles (178,444.189 km)
Diameter of orbit of Sun: 7,761,605.5 miles (12,491,093.2 km)
Circumference of orbit of Sun: 24,392,571.38 miles (39,256,038 km)
One degree along orbit of Sun: 67,700.05 miles (108,952.67 km)
One minute along orbit of Sun: 1129.283 miles (1817.405 km)