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

French Republican Twitter

@SansculotidesTwitter links in this post:

I have been following @JacobinCalendar on Twitter for a while. The Jacobins were a radical element of the French Revolution, who favored the French Republican Calendar. Unfortunately, they are known for the Reign of Terror, and were overthrown on 9 Thermidor Year II. Anyway, this feed generates two or three tweets a day giving the Republican Calendar date. For instance, today one says:
Today's date according to the French Revolutionary Calendar: Meadow/Cornflower/221
Meadow refers to the Republican month Prairial, which comes from the French word prairie, which means the same as in English, but it can be translated as "meadow", although then the month name should then be Meadowal... Cornflower refers to the so-called rural calendar, in which each day of the year was named for a plant, animal, agricultural tool or mineral, to replace the old saints' days. In French, today is called Barbeau, which is cornflower in English, although some sites translate it as barbel, because this is also the French word for this fish, but animal names are only used for quintidis, the fifth day of the 10-day décade, and today is Primidi, the first day of the third décade.

Of course, the usual way of giving the date is by day of the month, which would be 21 Prairial of Year CCXXI. I started tweeting dates like this, but I just discovered that someone was already doing so. Since the beginning of last Nivôse, the first month of winter, @Sansculotides has been tweeting the date every day like this:
Today is primidi 21 Prairial in the year of the Republic CCXXI, celebrating the cornflower. pic.twitter.com/I1O1FoWs62
This seems to be according to Paris time, however, since it's about 8 hours ahead for me.

Duodi 22 Prairial an CCXXI à 1 heure 84 minutes décimales t.m.P.
MJD 56453.177

Prairial app for Windows 8

Prairial by Laurent Rodier is a Windows 8/RT app that converts between the French Republican and Gregorian calendars. It displays the usual calendar girls for each month, and can display an entire month on one screen. It has live tile support, so it shows the date on your Windows Start screen. It also converts between standard and decimal times. It appears to display the current decimal time on a basic analog clock with 10 at the top. Since I don't have Windows 8 or RT, I have not tried it, but it's available for $1.49 in the Windows Market. It just happens that Prairial is the current month, the last month of spring.

Duodi 22 Prairial an CCXXI à 1 heure 24 minutes décimales t.m.P.
MJD 56453.117