Repsold Micrometers

Once the photographic plates for the Carte du Ciel program were taken, the positions of the brightest stars on each plate had to be measured, star by star. When the Specola moved to the former papal villa on the wall of the Vatican, a special room was set aside for a Gautier macromicrometer, which was originally used for these measurements. However, the Gautier instrument proved to be too slow for such a large program. Fr. Hagen decided to visit the various observatories which were already well along with the plate measurements. Based on their experience, he studied the best measuring techniques and determined that the best tool for the job was the micrometer from Repsold of Hamburg. Thus he obtained two Repsold micrometers, which proved to be precise and easy to use. The measurements were made by the Sisters of the Child Mary.