Caption: Taqi ad-Din (1526--1585), Ottoman era polymath, who built the Constantinople/Istanbul Observatory (1577--1580), at work in said Medieval/Early Modern Islamic-world observatory.

Yours truly guesses that Taqi ad-Din is the back-row fellow with the big turban showing an astrolabe to what may be Ottoman Sultan Murad III (1546--1595, reigned 1574--1595), also with a big turban.

Taqi ad-Din was the Istanbul counterpart to Tycho Brahe (1546--1601) who may have heard of Taqi ad-Din, but maybe NOT vice versa.

The chap at the upper left with an angle-measuring device appears to be the ghost of al-Sufi (903--986). Well, an extinct Wikipedia figure identified him as al-Sufi---a mistake probably---but very like a ghost.

Work in an observatory is the same today, mutatis mutandis.

Credit/Permission: Anonymous artist of Shahin-Shah-nama (Book of the King of Kings) (1581) by Persian poet Ala ad-Din Mansur-Shirazi (fl. 1580) (uploaded to Wikimedia Commons by User:Tetris L, 2008) / Public domain.
Image link: Wikimedia Commons: File:Taqi al din.jpg.
Local file: local link: taqi_ad_din.html.
File: Astronomer file: taqi_ad_din.html.