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    Re: V corrections?
    From: Gary LaPook
    Date: 2017 Mar 28, 08:57 -0700

    For some reason I remembered the siderial day was 23 hours, 56 minutes and 3.9 seconds. I just Googled it and it says 23 hours, 56 minutes and 4.091 seconds. I can't believe that it has chnged almost 0.2 seconds in my lifetime but I remembered looking it up somewhere, about 50 years ago, and that is the value firmly planted in my head. I just looked at my 1937 American Ephemeris and Nautical Almanac at it has the "4.091" value so, wherever I got the "3.9" value, it was erroneous. 

    I remember in my meteorology class, the professor was lecturing about the geostrophic wind equation and he said that "the earth turns 360 degrees a day" and I corrected him, that it turns 361 degrees in a day( in inertial space, relevant to the wind formula) and I got an eraser thrown at me.



    So i've been off by 0.191 seconds per day while doing my computations for the last 50 years. Let's see, there are 86,400 seconds in a day (I hope I didn't get that wrong too.)  So, 0.191 / 86,400 = 0.0000022106 or 0.00022% so I guess that error isn't large enough to explain away the inaccuracies in all those thousands of celestial computations I have done. 


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