I want to know the answer to the following question:
Who was the famous astronomer that Avicenna met before he left Khwarezm?
All the background I'm provided with is that "Aruzi Samarqandi describes how before Avicenna left Khwarezm he had met Al-Biruni (a famous scientist and astronomer), Abu Nasr Iraqi (a renowned mathematician), Abu Sahl Masihi (a respected philosopher) and Abu al-Khayr Khammar (a great physician).". Is that enough to answer the question?