Olof Hiorter in 1747. Olof Hiorter Olof Petrus (or Peter) Hiorter (or Hjorter) (1696–1750) was a Swedish astronomer. After studying in the Netherlands, he was appointed lecturer at the University of Uppsala in 1732 to fill the vacant position of Anders Celsius then on his grand tour of European observatories. From 1737 onwards, he studied together with Celsius the aurora phenomenon and a number of astronomy subjects (solar eclipse, comet like the one of 1744, latitude measurements). Pehr Wilhelm Wargentin was his pupil. Hiorter was elected a member of the Royal Swedish Academy of Sciences in 1745 and appointed "Observator Regius" -
Celsius value was 0.01023 °C with an uncertainty of 70 µK". This practice is permissible because the magnitude of the degree Celsius is equal to that of the kelvin. Notwithstanding the official endorsement provided by decision #3 of Resolution 3 of the 13th CGPM, which stated "a temperature interval may also be expressed in degrees Celsius", the practice of simultaneously using both °C and K remains widespread throughout the scientific world as the use of SI-prefixed forms of the degree Celsius (such as "µ°C" or "microdegrees Celsius") to express a temperature interval has not been well-adopted. One effect of defining the