Achim Leistner is an Australian optician of German origin.[1] He is the master optician of the Avogadro project, an international effort to define the Avogadro constant with maximum precision. He was asked to join the project from retirement as it was deemed that his expertise and craftsmanship were essential for the success of the project.[2]

Achim Leistner
Silicon sphere for Avogadro project.jpg
Achim Leistner at the Australian Centre for Precision Optics, holding a 1 kg, single-crystal silicon sphere for the Avogadro project.
Born20th century
Known forMaster optician of the Avogadro project
Scientific career

Leistner has made his career in the precision crafting of specialized optics. The Avogadro project needed a silicon sphere made to as high a precision as possible. The research team searched the world for manufacturing options and found Leistner's precision in handcrafting spheres superior to any machine. 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]

Leistner is in his seventies and has not found an apprentice who can match his precision. Once he retires from the project, the Avogadro team hopes that machines will have advanced sufficiently to match Leistner's capabilities.[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.

See alsoEdit


  1. ^ a b c Keats, Jonathon (27 September 2011). "The Search for a More Perfect Kilogram". Wired. Retrieved 16 June 2015.
  2. ^ Powell, Devin (1 July 2008). "Roundest Objects in the World Created". New Scientist. Retrieved 16 June 2015.
  3. ^ Episode 2: Mass and Moles. Precision: The Measure of All Things. BBC Four. 4 July 2014. 48.4 minutes in.