Pehr Wilhelm Wargentin was Swedish astronomer and demographer.
When Pehr Wargentin was 12 years old he observed a (total) lunar eclipse which would spark his lifelong interest in Astronomy. During his tenure at Frösö trivialskola (elementary school), his teacher deemed him advanced enough to continue directly to Uppsala University. However, Wargentin's father wanted him first to attend the gymnasium (secondary school) of Härnösand, which he did. In 1735, Wargentin matriculated as a student at the University of Uppsala, where he excelled. He graduated with the degree of filosofie magister (then the highest degree awarded in the Faculty of Arts) in 1743 and became a docent in astronomy in 1746 and an adjunct in 1748. He was called to Stockholm as secretary of the Royal Swedish Academy of Sciences in 1749 on the death of secretary Pehr Elvius, Jr., and stayed on this post until his death. Wargentin therefore became the first long-serving secretary of the Academy, which had been founded in 1739. He is seen as an important person in leading the Academy to its first golden era. Wargentin also became the first director of the 
Stockholm Observatory founded by the Academy of Sciences on the initiative of his predecessor, Elvius, and completed in 1753. He was elected a Foreign Honorary Member of the American Academy of Arts and Sciences in 1781. The crater Wargentin on the Moon is named after him.
A silver medal that was issued in 1783 – a work of Carl Gustaf Fehrman – shows Wargentin's portrait to the right. Legend around is: "PETRUS WARGENTIN EQUES AUR.".
On the reverse above the globe of Earth the Ecliptic runs from the Fish on the left to the Aquarius on the right. Close to this later the globe of Jupiter is visible. The moon Europa is placed right to it signed by '2' , while the other three moons are visible on the left: '1' is Io, '3' is Ganymede and '4' is Callisto. Text around "SUBLIMIORA IAM CURAT" means “he already cared sublime (matters)”, refers to his studies of Jupiter.
Another medal also mentions Wargentin's research work on Jupiter, although in rather allegoric form.
On the obverse, around the portrait to the left his position as a secretary of Academy is mentioned in the legend: "PETR · W · WARGENTIN REG ACAD · SC · SVEC · A SECRET · EQU · AUR ·". On the reverse allegoric scene with winged Prometheus is pictured, holding astrolabe in his hand. The text "ADSPECTAT OLYMPUM INQUIRITQUE JOVEM" means “he observed the Olympus and studied Jupiter”. Even if he did not steal the fire from the Olympus, he monitored most secrets of Jupiter, Father of Gods and men. Below the dates of his birth and death are displayed, 1717 - 1783.