Share this page on Twitter and LinkedIn!


NIST Time Lord, Dr Marc Weiss measured “625ps” of over night snow in his back yard using Chronos’ nanosecond rule in Boulder, Colorado

Lydbrook, Gloucestershire, UK, 2 April 2015, Chronos Technology’s “nanosecond” is a 12inch/30cm rule inspired by the training tactics of United States Navy Rear Admiral Grace Murray Hopper.  An American computer scientist, she invented the first compiler for a computer programming language,and was one of those who popularized the idea of machine-independent programming languages, which led to the development of COBOL one of the first high-level programming languages.

She was also the first person to use the term "debugging" when she discovered a moth stuck in the workings of an early computer.  She wrote to her management stating that the bug had been found and taped it to the letter.  Grace Hopper introduced the concept of roughly 12” of cable in her radar and communication classes illustrating how long it actually took radio signals to reach the satellite and get back to earth.  One of her lectures can be found on YouTube and indicates how she found this analogy very useful to explain to Admirals and Generals why there are delays in talking to someone via satellite.

Prof Charles Curry, founder and managing director of Chronos Technology discovered Grace Hopper’s history when touring the USS Hornet Museum in Oakland, California.  This inspired Chronos to create the 12” rule entitled “My very own nanosecond” to help to illustrate how GPS works.  These rules are distributed during Chronos training sessions and during workshops and symposia.

Dr Marc Weiss used the rule to measure snowfall.  Marc has worked at NIST for 36 years and has wide knowledge of time and timing, specifically GPS.  Together with David Allan (known for Allan Variance) Marc built the first GPS timing receiver in 1979 and they published joint white papers in the 1970s and 1980s.  Marc and Charles have worked together on WSTS and ITSF timing conference programmes for many years.

If we consider that 12” is just over one nanosecond, then 7.5” of snow in Marc’s back yard is equivalent to 625 picoseconds of snow and represents a novel metric to the world of metrology.

If you are delivering any training related to timing, Chronos would be delighted to send you enough nanoseconds for your delegates.  Please contact us at

About Chronos Technology

Chronos is an acknowledged expert in time, timing, phase and monitoring for telecoms, energy/utilities and banking/financial institutions.  Chronos offers a range of ‘PhaseReady™’ services designed to help network operators assess and prepare their networks for the challenges they face as they prepare to rollout LTE services. Chronos also designs SyncWatch™, the most versatile sync testing and measurement solution available on the market today, and TimePort™, a low power, lightweight, portable device that maintains time to within a few hundred nanoseconds of Coordinated Universal Time (UTC) in GPS denied locations.