NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
Re: "Sun Slow Day" is coming...
From: Hewitt Schlereth
Date: 2009 Feb 10, 22:01 -0400
From: Hewitt Schlereth
Date: 2009 Feb 10, 22:01 -0400
David Burch points out in Emergency Navigation that on Valentine's Day the sun is LATE to the meridian. Those of us who have ever been LATE with Valentines won't forget it. :-) Hewitt On 2/10/09, frankreed@historicalatlas.comwrote: > > Nicolas, you wrote: > "I knew these reactions were coming and to be honest: I would not even > trust the first digit, as I never tested the formula's I found to this > level and neither were they properly annotated. The reason that I gave > so many digits was the simple fact that even to change that last digit > takes almost 15 minutes." > > > Just so you know, I wasn't being facetious when I asked how much we could trust the digits. I'm just curious to see what results other people have had. I tried it myself by two sets of data today. In both cases, I tabulated GMT-GHASun and then fit a parabola to the curve for 48-72 hours around today's date. For the minimum value, I get 14m 13.8s which agrees with yours, as I would expect, but the time of the minimum is near 0230 GMT on February 11 which is about an hour and twenty minutes from now as I type this message. And that's about three hours earlier than your minimum. Getting the time of the minimum is of course very difficult since, just as you say, the value is arguably constant (indistinguishable from observations) for a few hours. > > Anyway, Happy Sun Slow Day! I have already done my celebratory fourteen minutes and fourteen seconds of procrastination for the day... several times over. > > I have a real personal reason for discussing this at length. For the past thirty years, since I first read about the Equation of Time, I have never managed to remember which way the signs go when I need it in practice. Inevitably, I always find myself double-checking. But knowing that February 11 is "Sun Slow Day" fixes all of the signs. With any luck, this discussion will keep it in my memory for good. :-) > > -FER > > > > > > > --~--~---------~--~----~------------~-------~--~----~ Navigation List archive: www.fer3.com/arc To post, email NavList@fer3.com To , email NavList-@fer3.com -~----------~----~----~----~------~----~------~--~---