John Harrison RAS Regulator 'Replica' - Video 1 of 13

John 'Longitude' Harrison's 'RAS' Regulator 'Replica', researched and constructed (to the displayed state) from early 2003 to late 2005.

This regulator, discovered after his death in 1776, was to be Harrison's final, most perfect masterpiece of land-based precision timekeeping technology, claimed to be capable of a mean rate within one second in a hundred days (the theoretical limit of performance for a purely mechanical 'clock' exposed to the atmosphere). Unfinished by Harrison and tragically ignored after his death in 1776, despite vast superiority over contemporary timepieces (and apparently, if the predicted performance is correct, never bettered by any purely mechanical, in-atmosphere timepiece throughout history).

Optimised single pivot grasshopper escapement, thirty seconds spring remontoire, Harrison maintaining gear, anti friction arbor supports, radial wheel teeth, roller pinions, caged rolling element bearings to the great arbor and Harrison gridiron pendulum with suspension cheeks. Those devices, when optimised, constitute Harrison's ideal combination of superior inventions.

Shown is an unpolished, uncased, 'visual near-replica' of the original, which is currently on display at The Royal Observatory, Greenwich, England. This 2005 'replica' was researched, designed and constructed over almost two years and is comprehensively described and explained in a book, 'Sleeping in Oblivion', published in 2007.

'Replicas' are currently being copied around the world, based upon dimensions and instructions supplied in the book (and I'll be watching this space for input from those constructors - come on guys and gals, get YouTubing - it's easy and great fun!).

Further details at http://soptera.blogspot.com and http://www.hsn161.com/HSN/Heskin.php
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Category:

Science & Technology

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