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Contemporary Muslim astronomers and engineers also constructed a variety of highly accurate astronomical clocks for use in their observatories , such as the castle clock ( a water-powered astronomical clock ) by Al-Jazari in 1206 , and the astrolabic clock by Ibn al-Shatir in the early 14th century .
 person: Al-Jazari; person: Ibn al-Shatir
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: location, person, organization 
Text: {0} 
Answer:
 person: Al-Jazari; person: Ibn al-Shatir