Caption: "Image of Avicenna (c.980--1037, AKA Ibn Sina), medieval manuscript entitled Subtilties of Truth, 1271." (Slightly edited.)

Avicenna is a famous Medieval Islamic Aristotelian and, stretching a point, Medieval Islamic astronomer.

He defended Aristotelian cosmology (see Wikipedia: Avicenna: Natural philosophy).

Credit/Permission: Anonymous Medieval Islamic artist, 1271 (uploaded to Wikipedia by User:Otfried_Lieberknecht, 2006) / Public domain.
Image link: Wikipedia: File:Avicenna.jpg.
Local file: local link: avicenna.html.
File: Astronomer file: avicenna.html.