@S1-A.ARPA,@MIT-MC.ARPA:koolish@bbncd2 (07/31/85)
From: Dick Koolish <koolish@bbncd2.arpa> Precession of the equinox has nothing to do with the Gregorian calendar. The Julian calendar was shifting with respect to the seasons because the year is not an integral number of days and the Julian calendar had it wrong. The Julian calendar had leap years every four years, which gave it 365.25 days per year. This is too many, since the year is 365.2422 days long. The Gregorian reform changed the calendar so that leap years were every four years except that century years were only leap years if they were divisible by 400. This gives a calendar year of 365.2425 days. By the time the Gregorian calendar was adopted, in 1582, the calendar was 10 days fast. When put into effect on October 4th, the next day became October 15th. The Gregorian calendar was adopted in England and the colonies in 1752 and not until 1918 by Russia. The Gregorian calendar still gives a year that is too long by 26 seconds so it will be one day off in 3200 years.
@S1-A.ARPA,@MIT-MC.ARPA:mcgeer%ucbkim@Berkeley (07/31/85)
From: mcgeer%ucbkim@Berkeley (Rick McGeer) Yea. We have a leap second periodically to even out the flaws in the Gregorian calendar. Just had one this year, in fact. Rick.
@S1-A.ARPA,@MIT-MC.ARPA:dsmith%hp-mars.csnet@csnet-relay.arpa (08/01/85)
From: David Smith <dsmith%hplabs.csnet@csnet-relay.arpa> > Yea. We have a leap second periodically to even out the flaws in > the Gregorian calendar. Just had one this year, in fact. The leap second is not to compensate for the Gregorian calendar, but for the fact that the earth's rotation on its axis is slowing down. The standard second is defined as 1/86,400 of a day in 1900 (I think averaged over the days of that year). The earth is rotating enough slower now to require leap seconds to keep the astronomical day and atomic clocks in sync. I am surprised that the precession of the equinoxes is described as a change in the ecliptic. The ecliptic stays (relatively) fixed; it is the earth's axis which precesses, carrying the celestial equator with it. David Smith ucbvax!hplabs!dsmith
mojo@kepler.UUCP (Morris Jones) (08/02/85)
> Yea. We have a leap second periodically to even out the flaws in >the Gregorian calendar. Just had one this year, in fact. I thought the leap seconds were to keep Coordinated Universal Time in sync within a second of astronomical time. Mojo MicroPro
john@frog.UUCP (John Woods) (08/06/85)
> From: mcgeer%ucbkim@Berkeley (Rick McGeer) > > Yea. We have a leap second periodically to even out the flaws in > the Gregorian calendar. Just had one this year, in fact. > > Rick. If I understand correctly, the leap seconds are not to correct the calendar, but are to correct for the slowing of the earth with respect to the atomic clocks. Leap seconds are added whenever the mood strikes the people who wind the atoms :-), not according to a fixed plan. -- John Woods, Charles River Data Systems, Framingham MA, (617) 626-1101 ...!decvax!frog!john, ...!mit-eddie!jfw, jfw%mit-ccc@MIT-XX.ARPA