PDA

View Full Version : Changing a calendar....



Lyra Jean
04-03-2011, 07:58 AM
What causes a calendar to change? I guess what I'm looking for is information as to what led the leaders to change the calendar we have a Julian calendar and a Gregorian calendar. What made these people decide to change the calendar. It had to be something big I'm thinking because well it didn't happen that often.

Kateness
04-03-2011, 08:21 AM
Okay. So, this is to the best of my understanding. We now operate under the Gregorian calendar. The reason for this is because the Julian calendar lost several days every couple of centuries because of the way it timed the year.

I guess that if you're dealing with a fantasy world, calendars can change as a greater knowledge of astronomy is developed.

Xelebes
04-03-2011, 08:25 AM
When the intercalary days have been incorrectly calculated, they adjust the calendar to the one that is consistent with the season needed. In equatorial cultures, they are more likely to use the lunar calendar, as the seasons play less of a role in harvesting, than the extratropical cultures, who use the solar calendar.

n3onkn1ght
04-03-2011, 11:56 AM
Well, the Shah of Iran, who was prone to throwing lavish celebrations, arbitrarily decided to change his country's calendar from the year of the Final Revelation of Muhammad to the birthyear of Cyrus the Great. They went from the 14th century to the 26th overnight.

He wasn't very popular.

Anne Lyle
04-03-2011, 12:14 PM
The French calendar was changed during the revolution, in an effort to break with the past:

http://en.wikipedia.org/wiki/French_Republican_Calendar

It didn't really work out, since no-one liked having only one day off every ten days, instead of every seven :)

jaksen
04-03-2011, 03:50 PM
A year in astronomical terms, the length of time it takes the earth to go around the sun is NOT exactly 365 days, or 365 and one quarter days. It's off. (You see the planets and sun DO NOT CARE about humans or how we measure time or any of that.)

So every so many centuries adjustments need to be made. We humans like order. We like four seasons, 12 months (why not ten), and 7 days to a week (why not ten? The French tried; big fail.) We try to divide things up the best we can. We end up with months with 31 days, 30 days, one with 28 days (except every four years) and do our damndest to fit ourselves into that one solar year, or revolution around the sun. It can't be done without adjusting things every so many centuries.

I don't know when the next big 'adjustment' will need to be. In a few centuries? Someone better versed in the subject can explain that. Also, scientists are always adding a second here or there to make up for lost time, whatever. (So maybe a big adjustment won't be needed.)

But basically, the years we were measuring did not line up with the orbit or revolutionary period of the earth around the sun. To fix things (as best they could) they jumped from one calendar to the next, losing a few days (I think) when it happened.

Must have been very confusing for those folks. Hey, yesterday was Sunday, but tomorrow is what? Friday? (This final example is in jest.)


(You know what else is kind of fun? The month of September means 7th month (but it's now the 9th.) October was the 8th month, November the 9th and December the 10th. But now they're the 10th, 11th and 12 months of the year. Amazing, what?)

Lyra Jean
04-03-2011, 06:58 PM
Thanks everyone for the insight. It's good to know it wasn't just arbitrarily changed at the whim of the rulers (mostly).

Oh yeah, I learned about the whole calendar thing in Roman History classes in college. March used to be the first month of the year because that's when the Romans could go back to war. How Julius Caesar and Augustus just stole days from other months to create their own months of July and August.

Anne- I think your answer is what I could use the best. A break from the past. My characters live on a space ship and their current calendar is Earth based because Earth wants it that way.

Xelebes
04-03-2011, 07:49 PM
Anne- I think your answer is what I could use the best. A break from the past. My characters live on a space ship and their current calendar is Earth based because Earth wants it that way.

There is more to that than just wanting it to be so. When it is about delivering or patrolling, the spaceship needs to know when to follow orders and when to signal that the orders have been carried out. Due to time differences (the spaceship might 5 lightyears away from Earth making a 5-year difference between communication: how are they supposed to know when the order came out and how fast or how high of a priority they are to carry out the order?

Prawn
04-03-2011, 08:02 PM
I have heard that April Fool's day had to do with the change from Julian to Gregorian calendar, but I may be wrong.

Lyra Jean
04-03-2011, 08:05 PM
There is more to that than just wanting it to be so. When it is about delivering or patrolling, the spaceship needs to know when to follow orders and when to signal that the orders have been carried out. Due to time differences (the spaceship might 5 lightyears away from Earth making a 5-year difference between communication: how are they supposed to know when the order came out and how fast or how high of a priority they are to carry out the order?

It's a colony ship heading for another planet and it's more to do with keeping Earth culture intact than anything else.

jaksen
04-03-2011, 09:35 PM
If they're working with Earth, they at least need to know the 'current' Earth calendar and keep track of it. Any calendar people use was created to make sense of time, to keep track of it, to know when the growing season was about to start, or when certain gods had to be appeased etc. etc. It's an attempt to put order into a world that sometimes is quite ... disorderly.

Sagana
04-03-2011, 09:40 PM
Lest anyone think the calendar wasn't arbitrarily changed on the whim of rulers, it was somewhat arbitrarily changed on the whim of the Pope.

The Julian calendar (established in 45BC to install a regular solar calendar instead of a very messy lunar one that required a group of "pontiffs" (who could be bribed) to add and remove days to keep the calendar in sync with the seasons) introduced an error of 1 day every 128 years (counting a year as 265.25 days). That error messed up the calculation of Easter.

Easter is calculated from the vernal equinox, which the Council of Nicea decreed 21 March. Using the Julian calendar, by 1582 when Gregory was Pope, the Vernal equinox had moved 10 days backward. Easter is tres important, so Pope Gregory dropped 10 days and instituted the Gregorian calendar. To keep things in sync, the Gregorian calendar only has 97 leap years in 400 years (a year is 365.2425 days rather than 365.25). So every year divisible by 4 is a leap year, except every year divisible by 100 isn't a leap year, except a year divisible by 400 is a leap year after all. (A later astronomer suggests the calendar is still a little off (should actually be 365.24225 days) and to fix that every year divisible by 4000 should also be a non-leap year, but that hasn't officially been adopted.)

Anyway in 1582 10 days were officially dropped from the calendar so 15 Oct. immediately followed 4 Oct. for Pope Gregory. Other countries willing to follow Papal decrees picked it up thereafter (and had different dates where the 10 days were dropped.) Catholic countries switched right away. Protestant countries took longer, and Greek Orthodox changed at the beginning of this century. Some orthodox churches still use the Julian calendar.

Sweden decided not to drop 10 days all at once, but to do it gradually by dropping leap years. Except they forgot and some years were leap years anyway. So they were all messed up and decided to go back to the Julian calendar, adding an extra day which gave them a double leap year. Later on they dropped 11 days (by that time) like everyone else.

The Gregorian calendar is useless for astronomy because there's 10 days just gone. Astronomers use the Julian Date Calendar to calculate positions backwards in time.

http://calendopedia.com/gregory.htm
http://calendopedia.com/julian.htm

Miriel
04-03-2011, 11:53 PM
If you want to look at a really cool calender...go read about the Maya. They were big into astronomy and making sure they knew exactly what day it was, calculating things thousand and thousands of years into the past and future. They were more interested in having the calendar be perfect that having it match up with harvest, so they didn't do leap years, adding months, etc.

There are two parts to it -- the first is the Long Count. It's actually a count of days from the creation of the world, broken into various units.

There's also the Calender Round, which repeats every 52-years.

Thinking about it, it would actually work pretty well for marking time accurately during space travel. Too bad it's not in wide use. :( But if you want to look at another calender system, this one's fascinating. And it comes with nifty glyphs.

Tepelus
04-04-2011, 12:31 AM
So, as long as we're on the subject of calenders, I've been wondering what people considered the first of the New Year to be in the 1400's (when my WIP takes place). Was it the first of January, or on the Vernal Equinox (and what day was it, the 21st or 22nd of March)? My chapter titles are the date, and my WIP spans many years. So when it comes to the New Year, I'd like to have confirmation as to when it actually is, not just for the titles, but for the story itself as well.

kaitie
04-04-2011, 12:37 AM
(You know what else is kind of fun? The month of September means 7th month (but it's now the 9th.) October was the 8th month, November the 9th and December the 10th. But now they're the 10th, 11th and 12 months of the year. Amazing, what?)

I think that was because the year was originally considered as beginning in the spring, thus March was considered the "first" month of the year rather than January, not because the calendar had to be rotated due to astronomical differences. Or something like that. And I so don't remember why it was changed to January. It's been awhile! It is crazy cool though, isn't it?

Anne Lyle
04-04-2011, 10:48 AM
So, as long as we're on the subject of calenders, I've been wondering what people considered the first of the New Year to be in the 1400's (when my WIP takes place). Was it the first of January, or on the Vernal Equinox (and what day was it, the 21st or 22nd of March)? My chapter titles are the date, and my WIP spans many years. So when it comes to the New Year, I'd like to have confirmation as to when it actually is, not just for the titles, but for the story itself as well.

From Wikipedia's article on the Julian Calendar:


During the Middle Ages (http://en.wikipedia.org/wiki/Middle_Ages) 1 January retained the name New Year's Day (http://en.wikipedia.org/wiki/New_Year%27s_Day) (or an equivalent name) in all Western European (http://en.wikipedia.org/wiki/Western_Europe) countries (affiliated with the Roman Catholic Church (http://en.wikipedia.org/wiki/Roman_Catholic_Church)), since the medieval calendar continued to display the months from January to December (in twelve columns containing 28 to 31 days each), just as the Romans had. However, most of those countries began their numbered year on 25 December (the Nativity of Jesus (http://en.wikipedia.org/wiki/Jesus)), 25 March (the Incarnation of Jesus (http://en.wikipedia.org/wiki/Annunciation), approximating the vernal equinox (http://en.wikipedia.org/wiki/Vernal_equinox)), or even Easter (http://en.wikipedia.org/wiki/Easter), as in France (http://en.wikipedia.org/wiki/France) (see the Liturgical year (http://en.wikipedia.org/wiki/Liturgical_year) article for more details).

In England, even before 1752, 1 January was sometimes treated as the start of the new year – for example by Pepys – while the "year starting 25th March was called the Civil or Legal Year". To reduce misunderstandings on the date, it was not uncommon in parish registers for a new year heading after 24 March, for example 1661, to have another heading at the end of the following December indicating "1661/62". This was to explain to the reader that the year was 1661 Old Style and 1662 New Style.

So it depends where you are writing about, and how complicated you want to make it :)

Kitti
04-04-2011, 08:37 PM
In the 1400s, in England, March 25th would definitely be considered the start of the new year. (As someone above mentioned, that's why Sept., our 9th month, comes from the Latin for 7, and similarly Oct, Nov, Dec.) The January 1st day crept in with the rise of almanacs, which were calculated to begin with January. Through the 17th century, you will often see all dates between January 1st and March 25th denoted as 1658/9 (for example) to indicate that it is still technically 1658 in England, though in other places it might be considered 1659.

One of the primary incentives to changing the date the year began had to do with Easter - because Easter is calculated on a lunar calendar, some years had 2 Easters, some had 1 and some didn't have any.

And on a random note, because no one mentioned it, there were all sorts of riots ("give us back our eleven days!") involved in the changing of the calendar year. People's birthdays were all messed up. In biconfessional towns on the continent, Protestants who kept the Julian calendar would go be obnoxious outside Catholic areas when they were trying to celebrate holidays according to the Gregorian calendar, and vice versa.

During the 1580s, when the whole Gregorian calendar thing was going down, England actually looked into doing their own new calendar that would be even "more correct" than the Pope's. Instead of correcting the dates back to the Council of Nicea, they were going to correct back to the birth of Christ which would involve the removal of four more days (hence the reason all our equinoxes and midsummer/midwinter are on the 21st's of the month instead of the original 25th's.) But the idea fell by the wayside and nothing ever came of it.

Tepelus
04-04-2011, 11:33 PM
How confusing! Maybe I'll do the 1479/80 like they did then (from January-March), to avoid confusion. The story takes place in Hungary and countries that now make up Romania, so I don't know if they would consider January 1st the New Year, or March 25th. For a while I thought it was March 25th, but now I'm not sure. The more I look into it, the more I become confused.

Kitti
04-05-2011, 04:51 AM
Unless the actual New Year's celebration is going to be featured in your story, you might want to consider arbitrarily making Jan. 1st the new year - many historians use this convention (with an appropriate note at the beginning of their books stating that they're going to do this) to avoid confusing their readers. All the dates you see on Wikipedia follow this convention (e.g. Edward VI is listed as having begun his reign in 1547, when according to the English calendar it would have still been 1546.)

Lyra Jean - getting back to your original question - is this a generation ship? Because it was quite common for medieval and early modern dates to actually be calculated according to the length of the monarch's reign (with the new year beginning on the anniversary of their coronation). I ask, because it would make a lot of sense to me for the colonists to reckon time according to the "reign" of their various captains. It could be something informal that crops up in the first years out from Earth, then gets deliberately formalized as the new calendar system.

DrZoidberg
04-05-2011, 12:29 PM
Pol Pot in Cambodia decided that Gregorian 1980 was year one. He still used the same calendar system of 12 months and 30/31 days. They did a lot of seemingly random things that in hindsight made no sense.

Lyra Jean
04-05-2011, 11:20 PM
Lyra Jean - getting back to your original question - is this a generation ship? Because it was quite common for medieval and early modern dates to actually be calculated according to the length of the monarch's reign (with the new year beginning on the anniversary of their coronation). I ask, because it would make a lot of sense to me for the colonists to reckon time according to the "reign" of their various captains. It could be something informal that crops up in the first years out from Earth, then gets deliberately formalized as the new calendar system.

It is a generational ship but the Original colonists are given nanobots so that they live "forever". In the book it is actually not even a new invention the nanobots were first used with astronauts to help them recover from the ravages of space flight. It's just they work so well none have died yet from natural causes.

I was going to hint at a failed cultural revolution near the end of the book after the successful suppression of the mutiny. Part of the cultural revolution was changing the calendar from an Earth calendar to one based on their new home among other things. Which leads to book two if it gets that far.

n3onkn1ght
04-06-2011, 02:11 AM
They did a lot of seemingly random things that in hindsight made no sense.

I think I'm going to nominate that for "Understatement of the Year". :)