bengsig@oracle.nl (Bjorn Engsig) (10/01/90)
[In which newsgroup should this me discussed?, let's try comp.misc] If you really want to dig into previous calendards, you will realize that it is actually very difficult. Here are a few of the ways different European countries changed from 'old' Julian Calendar to 'new' Gregorian Calendar: Denmark: 11 days omitted in February 1700. Sweden: Gradual change over 40 years (February 1712 had 30 days!). England: 11 days omitted in September 1752. Germany, Holland and others: Different for Catholics and protestants. -- Bjorn Engsig, Domain: bengsig@oracle.nl, bengsig@oracle.com Path: uunet!mcsun!orcenl!bengsig From IBM: auschs!ibmaus!cs.utexas.edu!uunet!oracle!bengsig
msb@sq.sq.com (Mark Brader) (10/13/90)
I've waited a few days before responding to this in the hope that either (1) I'd find the old Usenet article on the topic that I printed off some years ago, or (2) the person who posted it, or someone else who knows, would see this thread and follow up. However, the details in that old article were interesting enough that I believe I have remembered them accurately. Well, Bjorn Engsig (bengsig@oracle.nl) writes: > Here are a few of the ways different European countries changed from 'old' > Julian Calendar to 'new' Gregorian Calendar: > ... > Sweden: Gradual change over 40 years (February 1712 had 30 days!). In fact, if I am remembering the old article correctly, what happened in Sweden was even more interesting than that. In the year 1700 or 1704, Sweden *decided* to gradually change calendars by omitting 11 leap years, and that year was made a common (non-leap) year. But 4 years later, with more pressing matters demanding attention, they simply forgot about it and had a leap year after all. So Sweden remained one day out of step with its Old Style neighbors. This state of affairs persisted until 1712, when it was felt that this was getting pretty silly, and the calendar was put *back* to the Old Style by having a double leap year (a very uncommon year!), with, as noted, 30 days in February. Much later, in the late 18th or the 19th century, Sweden converted in the usual fashion by omitting 11 or 12 days (respectively). Now, Tim Goodwin (tlg@ukc.ac.uk) writes: > Aha, but the Russian system (where the year is a leap year iff the > remainder on division by 7 is 2 or 6) is actually more accurate* than > the Gregorian system, as well as not having the confusion at the end of > a century. which Geoff Clare (gwc@root.co.uk) notes can't be right: > There are approx. 365.242191 mean solar days in the tropical year. > The Gregorian system gives 365 + 1/4 - 1/100 + 1/400 = 365.2425 days. > The Russian system (as described by Tim, I don't know if he's right) > gives 365 + 2/7 ~= 365.285714 days. Even the Julian system (365.25 days) > was more accurate than that! Geoff is right, of course. I believe the actual Russian system is to have leap years every 4 years except in century years where the *century number* (or is it the year?) has to meet the criteria given by Tim. *This* gives a year of 365 + 1/4 - 1/100 + 2/700 = 365.242857+ days, which is indeed more accurate than the Gregorian system. But we'll see how *they* like being one day out of step, beginning on March 1 (Gregorian), 2200... An interesting point in all this is that when the Gregorian system was first proclaimed in the 16th century, only 10 days were dropped. This means that, extrapolating backwards, the Julian and Gregorian calendars would agree not in the 1st century BC, when the Julian calendar was started, nor in the 1st century AD, which might be thought especially significant to the Roman Catholic Church, but rather in the *3rd* century AD, or more precisely, from March 1, 200, through to February 28, 300. Finally, Karl Heuer (karl@haddock.ima.isc.com) notes: > Interestingly, the approximation 365 + 1/4 - 1/128 is simpler, better suited > to binary computation, and over four times more accurate. He's right; it yields 365.2421875 days. Supposing that this calendar was made to agree with the Julian calendar beginning in the year 256 (to keep with the above), then the subsequent omitted leap years since then would be 384, 512, 640, 768, 896, 1024, 1152, 1280, 1408, 1536, 1664, 1792, and 1920... numbers much easier for anyone to remember than the silly 1700, 1800, 1900 stuff! Note incidentally that there were 13 years in that list, and the Julian and Gregorian calendars are now 13 days apart. This means that the Gregorian and Heuerian calenders are currently in agreement. This alignment would change in 2048, when the Heuerian (Lintian?) calendar omits a leap year, but it and the Gregorian then come back into line in 2100, only to separate again in 2176, come together again in 2200... A further advantage of the Heuerian system is that the total number of days in its overall cycle, 128*365 + 31 = 46751, is not a multiple of 7 as is the corresponding number in the Gregorian system, 400*365 + 97 = 146097 = 7*20871. This means that in the Heuerian system a particular date is equally likely to be any day of the week. In the Gregorian system, Christmas occurs on a Monday only 7/50 of the time; in the Heuerian system, this event gets its proper probability of 1/7. I think Karl has a great idea. Let's adopt it in Canada at once! :-) -- Mark Brader, SoftQuad Inc., Toronto, utzoo!sq!msb, msb@sq.com A standard is established on sure bases, not capriciously but with the surety of something intentional and of a logic controlled by analysis and experiment. ... A standard is necessary for order in human effort. -- Le Corbusier This article is in the public domain.
myamin@cbnewsm.att.com (m.yamin) (10/14/90)
From article <1990Oct13.101434.21356@sq.sq.com>, by msb@sq.sq.com (Mark Brader): > [When the Gregorian calendar ....] > was first proclaimed in the 16th century, only 10 days were dropped. > This means that, extrapolating backwards, the Julian and Gregorian > calendars would agree not in the 1st century BC, when the Julian > calendar was started, nor in the 1st century AD, which might be > thought especially significant to the Roman Catholic Church, but > rather in the *3rd* century AD, or more precisely, from March 1, > 200, through to February 28, 300. > I think Pope Gregory XIII's intention was to reset the calendar back to what it was at the time of the Council of Nicaea (325 AD) which established the rule for the date of Easter. The problem with the Julian calendar was that Easter and associated observances (like Lent), which are keyed to the spring equinox, were backing up toward Christmas. Why he dropped 10 days rather than 9 I don't know. M. Yamin my@syscad.att.com
diamond@tkou02.enet.dec.com (diamond@tkovoa) (10/15/90)
In article <1990Oct13.101434.21356@sq.sq.com> msb@sq.sq.com (Mark Brader) writes: >But we'll see how *they* like being one day out of step, beginning on >March 1 (Gregorian), 2200... It isn't necessarily a problem. One would think that along the International Date Line, some islands might be 23 hours ahead of their neighbors, and it might have the same appearance as being one day out of step. However, the Date Line is rather skewed, so some locations that should be experiencing a particular date are actually experiencing the preceding date or the following date instead. If I remember correctly, some locations are as much as 25 or 26 hours ahead of their neighbors. -- Norman Diamond, Nihon DEC diamond@tkov50.enet.dec.com (tkou02 is scheduled for demolition) We steer like a sports car: I use opinions; the company uses the rack.
karl@haddock.ima.isc.com (Karl Heuer) (10/18/90)
In article <1990Oct13.101434.21356@sq.sq.com> msb@sq.sq.com (Mark Brader) writes: >Finally, Karl Heuer (karl@haddock.ima.isc.com) notes: >>Interestingly, the approximation 365 + 1/4 - 1/128 is simpler, better suited >>to binary computation, and over four times more accurate. > >He's right; it yields 365.2421875 days. Supposing that this >calendar was made to agree with the Julian calendar beginning in >the year 256 (to keep with the above), then the subsequent omitted >leap years since then would be 384, 512, 640, 768, 896, 1024, 1152, 1280, >1408, 1536, 1664, 1792, and 1920... numbers much easier for anyone to >remember than the silly 1700, 1800, 1900 stuff! Correction. The proposed change is synchronized to the year 100, and the Heuerian omitted leap years are 180, 200, 280, 300, 380, 400, 480, 500, 580, 600, 680, 700, and 780... numbers much easier for anyone to remember than the silly (Gregorian) 6a4, 708, 76c stuff! Who needs to memorize the *list*, anyway? For everyday applications all you need to know is how soon the next unleap is coming, and for that you've got 80 (0t128) years of advance notice. In article <1990Oct15.013318.19836@tkou02.enet.dec.com> diamond@tkou02.enet.dec.com (diamond@tkovoa) writes: >In article <1990Oct13.101434.21356@sq.sq.com> msb@sq.sq.com (Mark Brader) writes: >>But we'll see how *they* like being one day out of step, beginning on >>March 1 (Gregorian), 2200... > >It isn't necessarily a problem. One would think that along the International >Date Line, ... There's a difference, though. The result of the IDL skew is that when it's Thu 08-May in one location it's Fri 09-May in another. The result of a not-quite-Gregorian calendar is that it would be Thu 08-May in one location and Thu 09-May in another. You couldn't buy a calendar in country X and use it in country Y! Karl W. Z. Heuer (karl@ima.isc.com or uunet!ima!karl), The Walking Lint
diamond@tkou02.enet.dec.com (diamond@tkovoa) (10/19/90)
In article <18557@haddock.ima.isc.com> karl@ima.isc.com (Karl Heuer) writes: >In article <1990Oct15.013318.19836@tkou02.enet.dec.com> diamond@tkou02.enet.dec.com (diamond@tkovoa) writes: >>In article <1990Oct13.101434.21356@sq.sq.com> msb@sq.sq.com (Mark Brader) writes: >>>But we'll see how *they* like being one day out of step, beginning on >>>March 1 (Gregorian), 2200... >>It isn't necessarily a problem. One would think that along the International >>Date Line, ... >There's a difference, though. The result of the IDL skew is that when it's >Thu 08-May in one location it's Fri 09-May in another. The result of a >not-quite-Gregorian calendar is that it would be Thu 08-May in one location >and Thu 09-May in another. You couldn't buy a calendar in country X and use >it in country Y! Ah, I see the difference. But msb's problem (most significant problem :-) also isn't so difficult. I hung a small calendar on one of my terminals. For today's date it says in large characters "19", and in small characters (roughly) "old 9th-month 1st-day". It is metal-weekday (Friday) under both the old calendar and the modern calendar. I would guess that the old calendar was imported from China, and the old 1st-month 1st-day would coincide with Chinese New Year. I understand that in the middle-east (on various sides of various battles), the month number and date number also differ from those in western countries, and possibly from each other. -- Norman Diamond, Nihon DEC diamond@tkov50.enet.dec.com (tkou02 is scheduled for demolition) We steer like a sports car: I use opinions; the company uses the rack.
hclase@kean.ucs.mun.ca (Howard Clase, Chemistry, MUN) (10/22/90)
In article <1990Oct19.011937.4931@tkou02.enet.dec.com>, diamond@tkou02.enet.dec.com (diamond@tkovoa) writes: > I understand that in the middle-east (on various sides of various battles), > the month number and date number also differ from those in western countries, > and possibly from each other. > -- Sounds a great idea! That way the two sides can fight on the same date, but on different days and noone gets killed. :-) Howard.