International Astronomical Union

The International Astronomical Union (IAU) has been using decimal time in its telegraphed circulars for over a century. Following the recommendations of the IAU, the dates of observations, or of astronomical events, should be written in the order of year, month, day, so that in principle it can be appended by the decimal fraction of a day. An example decimal time would be 2023 Nov. 3.1234 UT, where .1234 is the time of day represented as a fraction. All times are Universal Time (GMT). This fraction is identical to MJD, but with a Gregorian calendar date. 

 For an actual example, see IAU circular

History

You may wonder, what did decimal time actually look like in history? I’ve read thousands of records from the Revolution and can tell you. See here for actual examples.

Web clock

I just noticed that the HTML5 clock on this page shows Comic Sans on Windows PC instead of cursive. I think I have now fixed that. I also added some drop shadows to make it look more 3D. There is also now a little hand for day of the week (décade) which is also indicated by text, (Decadi, Primidi, etc.) Let me know what you think. There is a larger version here. 

It’s blue, white, and red to match the tricolour flag, with a Phrygian cap to celebrate the French Revolution. It’s written in HTML5 and JavaScript. I made my first decimal clock in AT-BASIC over 40 years ago. That one was more…basic. I used to have Java clocks ⏰ 🕰️ on my old website, but this one’s better. 

Rey-Pailhade clock

A decimal clock built in the 1890s, dividing the day into 100 parts. Midnight is a the bottom and there is only one hand. 

J. de Rey Pailhade (designer)

Decimal System Wall Clock, Systeme J. De Rey Pailhade 

L. Leroy & Cie, Paris: c. 1890s

Enamel face, gilt hour hand, glazed lid, mahogany case

21.5 inches diameter

Source

Salut et Fraternité

Get decimal time on your watch! 

My favorite decimal time app for iPhone, Salut et Fraternité by Olivier Noel (Brumaire), has just been updated for the first time in five years. Version 2.8 includes an Apple Watch app. The app shows the Republican date and decimal time, with an analog display resembling an old-style pocket watch face. There is also a widget for your iPhone Home Screen. 

It now supports both the original, equinox, rule, as well as the “Romme” 4-year rule. (“Romme” actually calculates leap years one year before others count it, so that it starts with year 3 as a leap year.)

[App Store]

Twitter

X, formerly Twitter, seems to be going down the drain. Not just in obvious ways  There used to be a number of accounts which tweeted the Republican calendar date daily. Together, they have thousands of followers! I don't know if they're cracking down on bots, or raising prices, or what, but they've been shutting down over the past few months. 

Fromental Halévy

Fromental Halévy (27 May 1799 – 17 March 1862), was a French composer. The name Fromental (meaning 'oat grass'), by which he was generally known, reflects his birth on the day dedicated to that plant: 7 Prairial in the French Revolutionary calendar, which was still operative at that time. Children were supposed to be named from the new calendar, instead of the Catholic Calendar of Saints.

Decimal Time meeting

 

John H is inviting you to a scheduled Zoom meeting.

Topic: Decimal time 

Time: 60120.1 (Saturday 7:24 PDT)

Join Zoom Meeting

https://us04web.zoom.us/j/8111168381?pwd=wYCYSf16OE0uE4Ebu5XrJ2WwM0DKGb.1

Meeting ID: 811 116 8381

Passcode: decimal

Opinion Day

In the French Republican calendar, the penultimate day is Opinion Day, apparently being the only day allowed for free speech. Here is what they wrote about it: 

      The quintidi, fifth and last of the Sanculottides, will be called the Feast of Opinion. Here rises a tribunal of a new kind, both gay and tetrible. 

First decimal watch