10 hours a day, 10 days a week

I now have a decimal clock with 10 hours and French Republican wall calendar with 10 days a week. Instead 27/7 I can do 10/10!

As you can tell from the position of the hands, it's really a standard clock with a faux decimal face, so the hour hand goes around twice a day and the other hands like usual, but it looks cool. I used a gift card from my secret Santa to get the clock from Cafe Press and bought the calendar from Etsy. You can see more pictures on Twitter.

Duodi 22 Pluviôse an CCXXIV à 9 heures 53 minutes décimales t.m.P.
MJD 57429.947


Leap day

The autumnal equinox comes at MJD 56923.10331 (Tuesday, 2014-09-23 02:28:46 UT) in the Northern Hemisphere. Because that is 366 days after the previous one, the day before, 56922 (this Monday, Sept. 22), is a leap day in the French Republican Calendar. There are usually five complementary days at the end of the Republican year, sometimes collectively called Sansculottides, but this year there is a sixth complementary day, which is why the Republican leap year is called sextile. This day was called Fête de la révolution (Festival of the Revolution), commemorating the French Revolution.

Some people convert modern French Republican Calendar dates by using a rule like the Gregorian calendar, which usually has leap years every four years. This makes it easier to calculate, and is probably what the French would have eventually done, had they kept their calendar, but they did not. By this rule, 56922 (Mon., Sept. 22) is not leap day but actually New Year's Day, the first day of the month of Vendémiaire in the 223rd year of the Republic.

Leap day or New Year's Day, either way it's cause to celebrate!

Quartidi 4e jour complémentaire an CCXXII à 2 heures 95 minutes décimales t.m.P.
MJD 56920.289


Almanach national de France

I found a copies of the Almanach national de France on the Bibliothèque nationale de France web site. The edition for the second year of the Republican Calendar (l'an deuxieme), 1793-94, includes astronomical tables with decimal times. You can also see the times for the equinoxes and solstices and the phases of the moon written out.

For example, here is the Republican Calendar month of Nivose, in nouvelles heures, or "new times". It says
Solstice á 3 heures 20 minutes 64 secondes. HIVER.
Dernier Quartier á 5 h. 28 m.  Premier Quartier á 7 h. 10 m.
Nouvelle Lune á 9 h. 92 m.    Pleine Lune á 1 h. 53. min.
Hiver is winter. The phases (top to bottom then left to right) are last quarter, new moon, first quarter, full moon.

As I have pointed out before, I usually see decimal times today written with colons, although using colons was not common back then, but rather h and m. Using a decimal mark (which is the comma in French) would make more sense. Even today it is common in French to use h and m with standard time. Here you see a decimal time for the winter solstice written out in full with hours, minutes and seconds, corresponding to 3.2064 decimal hours, and the rest abbreviated, corresponding to 5.28, 9.92, 7.10 and 1.53 decimal hours.  Where there is room, minutes are abbreviated as min., or m. where there is not.

Therefore, I prefer using the old-style French notation, as shown here.

I can tell that most of the times are "true time", or local apparent solar time, which varies throughout the year in relation to mean time, and is shown by sundials. The last column shows when true solar noon occurs in local mean time. All times are relative to Paris.

Quartidi 14 Fructidor an CCXXII à 10 h. 84 m. t.m.P.
MJD 56900.077

Swatch on TLDR

The NPR program On the Media publishes a podcast and blog called TLDR, which is an Internet abbreviation for "too long; didn't read". On MJD 56896.7 (August 27) they re-released a podcast originally released on 56701.6 (February 13), which was about Swatch's Internet Time.  You can listen to the podcast and read the transcript.

MJD 56900.021


Stardates and Julian Dates

I posted a year ago about a printed source I found stating that, as I had long suspected, stardates were based on Julian Dates.  I was reviewing the Memory Alpha page on stardates and came across some information on the subject, which had originally been posted on Star Trek Fact Check.  Apparently, the use of the Julian Day system was suggested by Kellam de Forest (not to be confused with DeForest Kelley) who worked as a script researcher.  Here are some notes he made on the (second) pilot:

(Page 2, Scene 3) 
But on star date 1312.4 – Astronomers already have adopted a method of dating which makes possible the counting of the number of days elapsed between widely separated observations called 'the Julian Day'. Today July 14, 1965 is 2,438,956 in Julian days.  A Julian cycle is 7,980 years, and the Julian day measurement would be scientifically authentic. Suggest “on Julian B 1312.4”.  This date would be August 5, 3271.
(Page 65, Scene 175) 
C-1277.1 to 1313.7 – We presume dates are in days, Kirk would only be 36 days  old.  For conventional dating suggest 3235 to 3271.  For Kirk’s birth date in Julian system figure would be in millions.  If desired, can be calculated.
He seems to be assuming that the show was set a thousand years in the future of when it was later established to occur.  Kirk is now considered to have been born in 2233, and the five-year mission took place in the late 2260s.  Since the Julian Period lasts 7980 years and the current one began in 4713 BCE, the next Julian Period begins on January 1 of the year 3268.  Thus, a Julian Date of 1312.4 would be 1,312 days, or about three-and-a-half years, later, on August 5, 3271, as he says.  Presumably "Julian B" refers to the next Julian Period, so the current one is Julian A.

It has long been a mystery what exactly C-1277.1 means on Kirk's tombstone.  Obviously, Kirk is more than 36 days old; more like 36 years.  Some have suggested that C stands for "captain", and that these are the dates of his command.  But perhaps it's for Julian C, indicating that the first stardate is in a different period than the second, although it's hard to infer the specifics.  The year 3235 lies between Julian days 2,902,620 and 2,902,984.  But it appears that somebody else picked the stardates, and de Forest was trying to retcon them as Julian Dates.

So we now have a genealogy going back to the French Revolution, starting with the Republican Calendar and decimal time, which passed into astronomy through Laplace, being combined with Herschel's Julian days, eventually to inspire the creation of stardates.

MJD 56598.357


Bonne année!

Today at 20:44 Universal Time (56557.8638), 8h 70m Paris mean decimal time, summer officially ends and fall begins in the Northern Hemisphere.  It was also on this date in 1792 the the First Republic was declared in Paris during the French Revolution. This marked the beginning of what was soon to be known as the Republican Era, which was to replace the Common Era of Anno Domini.  Each year of the new era began on the autumnal equinox.  The year was divided into 12 months of exactly 30 days, with five or six extra days at the end of the year treated as holidays. Instead seven-day weeks, each month was divided into three décades of ten days each. Each day was divided into ten hours, each decimal hours into 100 minutes, and each decimal minute into 100 seconds. Decimal time never caught on, although clocks were made and some used it for a while.  The astronomer Pierre-Simon Laplace had a decimal watch and used decimal time in his work, and to this day astronomers still use decimal time to date the observations of stars and other objects, which became the inspiration for Star Trek's stardates. The ten-day weeks were abandoned in 1802, and the rest of the calendar was abolished by Napoléon in 1806. Events during the French Revolution are still referred to by their Republican calendar dates, and lobster thermidor gets its name from the 11th month. 

The Gregorian date, September 22, 2013, begins the year 222 of the Republican Era, the 1st day of the month of Vendémiaire.

MJD 56557.330


iPhone and iPad apps

Apps in this post:
CalRep by Jacques Lafon (MuppetJack)

I have more apps for iPhone and iPad. Since I've been posting about the French Republican Calendar, I'll post about those first. I've talked earlier about CalendrierSalut et Fraternité for iPhoneSalut et Fraternité for iPad and revol-di. Now we have some more.

CalRep by Jacques Lafon (MuppetJack) is a universal app (meaning it is designed for both iPhone and iPad). Originally released October 2, 2012 (56202, CCXXI/1/11), version 2.1 November 5, 2012 (56236, CCXXI/2/15).  It is free, with $1.99 in-app purchase for the "complete version".  I don't know what that means, and I'm not going to pay before I find out. In addition to the current date, you can convert between Gregorian and Republican dates for any year after I. I found one bug: all the Roman numerals for years are wrong on the selector, e.g. the current year 221 shows CCXX, although on the iPhone (but not iPad) the year is also correctly shown next to the picture. It starts in 1792 as "Yr (1) / Yr I (2) / Yr II (3)…" It sends daily alerts, which I like, and you can set what time to receive them, although for some reason you can't get them before 9 am, which is late for me. The dates are calculated according to what I call the continuous rule,  which is the fixed rule that leap days are added before (not after) most years divisible by 4, which is continuous with leap days during the Revolution, although those were determined by the equinox rather than a fixed rule, so sometimes it's a day off from the equinox date in some years. It does not show the decimal time, but it does show for each date the month's calendar girl and a picture of the rural calendar name, although for today it shows the barbel fish instead of the cornflower (barbeaux)! (See previous post.) It also has links to Wikipedia articles, although some of them don't exist, as such. Unlike some of the others, it does not show decimal time.

Update: The CalRep app is no more. It has been updated to version 3.0 and renamed UniCal - Universal Calendar, with a new icon, and now includes a bunch of other calendars, including Chinese, Mayan, Hebrew, Islamic and Persian. (What, no Julian/Orthodox?) The year number bug has been fixed.  Also, you can now get alerts as early as 5 am, although it does not always work for me.  The years appear to begin on the equinox.  I just noticed that only half the day-names appear; every other day says "Free Version", so now I guess I know what the difference is.  Maybe that's why I'm only getting half the daily notifications. 56477.131 (Sextidi 16 Messidor an CCXXI à 1 heure 37 minutes décimales t.m.P.)

Calendrier républicain by Hachette Livre is also a free universal app, released on September 3, 2012 (56173, CCXX/12/17).  It converts between Gregorian and Republican dates, and also converts French day names (like Barbeaux) to dates, although you have to scroll through an unsorted list of 366 names! However, like revol-di, it only works for dates during the Revolution, itself. But you can use it to find current dates if you add 220 to the year. It also does not show decimal time.

TI:ME by Alexander Clauss is a 99¢ universal app, released November 2, 2012 (56233). It displays the current time in any of the following formats: decimal, local standard (24-hour, 12-hour or AM/PM), standard in other timezones, Braille, hex, octal, Swatch Internet Time (.beat), NATO DTG, trig (degrees or radians), or with numbers represented by symbols on the periodic table of elements. There are various settings for each clock.

Geek Time Pro by reizverstaerker medienwerkstatt OG is a 99¢ iPhone app, released August 9, 2011 (55782). It displays the time in binary coded sexagesimal (lights or 1/0), binary coded decimal (BCD), hex time or decimal time.

Duodi 22 Prairial an CCXXI à 2 heures 42 minutes décimales t.m.P.
MJD 56453.236