![Achim Leistner is an Australian optician of German origin.[1] During his retirement, he was asked to join the Avogadro project to craft a sili](https://upload.wikimedia.org/wikipedia/commons/thumb/5/56/PrecisionOptics_Achim2.jpg/1200px-PrecisionOptics_Achim2.jpg "Achim Leistner - Wikipedia")
Achim Leistner - Wikipedia
Achim Leistner is an Australian optician of German origin.[1] During his retirement, he was asked to join the Avogadro project to craft a silicon sphere with high smoothness, as automated machining does not match his precision.[2]
In addition to precision instruments, Leistner uses his hands to feel for irregularities in the roundness of the sphere.[1] The research team has called his extraordinary sense of touch "atomic feeling".[3] As a result the sphere is the roundest man-made object ever manufactured in the world. If the sphere was scaled to the size of Earth, it would have a high point of only 2.4 m (7 ft 10 in) above "sea level".[Note 1]
Leistner holds certificates in precision optics, geometrical optics, optical design drawing, and mathematics from Optic Carl Zeiss Jena Technical College. He has served as a member of the Australian Optical Society and on international conference working committees for SPIE and the Optical Society of America.[4]
