NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Chronometers
From: Alexandre Eremenko
Date: 2008 Mar 26, 11:55 -0700
From: Alexandre Eremenko
Date: 2008 Mar 26, 11:55 -0700
Dear list members, I think that of all (archeo)-navigation topics, chronometers were not discussed on this list in all detail. I recently purchased one (a late Soviet one), and I have many questions. 1. In the general books about chronometers (NOT the navigation books) they say that it is not important that a chronometer shows "exact time". The important feature is the "constancy of rate". For example, if a chronometer shows 24 hours and 1 second for each 24 hours period, this is a good chronometer, because you can have an easy correction formula: True time=(Chronometer time) minus (the number of days since the last checkong) seconds. My question: what was the normal practice in XIX and early XX century. Did they routinely determine the daily rate and then used a linear correction formula True time=(chronometer time) plus (the daily rate) times (the number of days since the last checking) plus constant? Or they just tried to regulate a chronometer to have zero daily deviation and then used the time it shows as the true time? Somehow I cannot find the answer in the navigation manuals and even in Chauvenet. 2. Since I bought my chronometer, I put it on test, that is I wind it regularly and check against a good electronic watch. (The electronic watch I check every month against GMT on the internet). The experiment (which is running for about 1 month already) shows that the chronometer is slow by 1.4 seconds every day in the average, and if I add this correction, the chronometer time is accurate within 1 second most of the time. Is this a good chronometer? The factory certificate says that the maximal daily "going" has to be at most 3.5 sec, and this particular one showed 1.3 seconds on the factory test. 3. There was a funny story of purchasing this chronometer (from Russia) which I can tell if there is any interest:-) Alex. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---