Al-Battani / Batani from Damascus discovered how long a solar year was, only missing the correct value by 2 minutes 22 seconds. Muslims built a great many observatories, but the largest observatory in the world in its time was built at Maraghah in 1258 A.D. (657 A.H.)
Al-Battani/Batani kutoka Dameski aligundua ni jinsi mwaka, uliohesabiwa kutegemea jua, ulivyokuwa mrefu, lakini alikosea thamani ya urefu wake halisi kwa dakika 2 na sekunde 22. Waislamu walijenga sehemu nyingi kubwa za tathimini na matazamio, lakini kubwa kuliko zote duniani kwa wakati ule ilijengwa Maraghah mnamo mwaka 1258 BK (657 BH).