NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: Chronometer Suggestions
From: Paul Hirose
Date: 2009 Jan 11, 09:18 -0800
From: Paul Hirose
Date: 2009 Jan 11, 09:18 -0800
It may be interesting to look at the seasonal variations in daily rate of an ordinary battery powered wall clock. I check this clock monthly, so the values are the average daily rate for the month. All values are positive, i.e., the clock always runs fast. 2006 2007 2008 Jan .40 .38* .37 Feb .40 .45 .39 Mar .38 .46 .44 Apr .43 .46 .45 May .47 .50 .50 Jun .48 .52 .52* Jul .40 .48 .50 Aug .48 .48 .49 Sep .47 .50 .52 Oct .44 .47 .49 Nov .41 .41 .46 Dec .35 .38 .41 * new battery installed at beginning of this month And here are values for a $25 Timex digital watch I bought in 2000. It still has the original battery. I don't wear this watch a lot; probably less than 5 hours per week. 2006 2007 2008 Jan .43 .41 .42 Feb .40 .42 .42 Mar .41 .43 .45 Apr .41 .41 .43 May .39 .41 .42 Jun .34 .40 .38 Jul .26 .35 .34 Aug .35 .34 .34 Sep .40 .40 .40 Oct .43 .45 .43 Nov .43 .44 .46 Dec .41 .43 .44 The time checks are by eye and ear using WWV on a cell phone. By comparing the phone audio to the audio from a shortwave receiver I've found that the phone is consistently 1/4 second late, as well as I can estimate, so this constant is disregarded. My monthly error checks are accurate to perhaps 1/4 second, so the corresponding daily rate is probably accurate to plus or minus .01 second. -- I block messages that contain attachments or HTML. --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---