Olof Hiorter 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" - "Royal Astronomer"
Celsius same is "40°C ± 3 K", which can be commonly found in literature. Celsius measurement follows an interval system but not a ratio system; and it follows a relative scale not an absolute scale. For example, 20 °C is not twice the heat energy of 10 °C; and 0 °C is not the lowest Celsius value. Thus, degrees Celsius is a useful interval measurement but does not possess the characteristics of ratio measures like weight or distance. In science and in engineering, the Celsius scale and the Kelvin scale are often used in combination in close contexts, e.g. "a measured