NUMPTi

A fullscreen web clock implementing a proposed metric/decimal time system that divides the day cleanly while keeping the second unchanged and reducing single-point ambiguity at transitions.

NUMPTi stands for New Universal Metric Partitioned Time — styled as NUMPTi because the trailing lower-case i is part of Time.

This repository is a static site (no build step) designed to be hosted on GitHub Pages.

What you get

• Fullscreen decimal clock with selectable formats:
  • Colon: HH:M(:SS) where HH = 00–95, M = 0–9 (single digit), SS = 00–99
  • Brackets: HH(M)SS (minute is always in brackets, single digit 0–9)
  • Examples: 74(8)01, 46(), (6)08
• Overlap/crossover support: optionally show the alternate reading during the overlap window (indicated by ◐ symbol).
• Analogue mode: 96-hour dial with hands for day-progress (hour), minute-in-hour, and optional seconds. Minute labels (0-9) appear at key positions (every 24 hours) when enabled via checkbox.
• Built-in “How it works” panel: a quick explanation of the system, overlap, and date format inside the app.
• Midsun (solar noon) helper: optional geolocation (or manual longitude) to show the midsun point in decimal time and the time delta to/from it.
• Converters:
  • Unix time (seconds or milliseconds) → decimal
  • Conventional wall time + UTC offset → decimal (useful for "different timezones" without relying on IANA/DST rules)
• Unit tests for the core conversion maths (node --test).

Time system specification (implemented)

Core divisions

• The day is exactly 86,400 seconds (unchanged from standard time).
• The day is divided into 96 hours (numbered 0 to 95).
• Each hour is exactly 900 seconds (= 15 standard minutes).

Minutes + seconds

• Each hour has 9 normal minutes (numbered 0 to 8).
• Each normal minute is exactly 100 seconds.
• Seconds within the minute: 00–99.

Crossover / overlap minute (9)

• During the first 100 seconds of each hour, the physical time interval can be labelled in two ways:
  • Current hour, minute 0, or
  • Previous hour, minute 9 (the "overlap minute")
• This spreads the boundary over a window instead of a single instant.

Example around the change from hour 47 to 48:

Physical time interval	Primary label	Alternate label
last 100s of hour 47	47:08	—
first 100s of hour 48	48:00	47:09
next 100s of hour 48	48:01	—

The clock advances through the overlap showing both 47:09 and 48:00 for the same physical moment.

Daily reset

• After hour 95, minute 8 (end of normal hour 95), the clock shows 95:09 (crossover minute).
• The next period is displayed as 0:00 (start of the new day).
• The same 100-second crossover window exists at the day boundary.

Display formats

The app supports two digital formats:

• Colon: HH:M(:SS) — minutes are single digit 0–9
• Brackets: HH(M)SS — minute is always inside brackets, single digit 0–9
  • Examples: 74(8)01, 46(3)99, 12(0)45
  • If minute is hidden, brackets are kept empty: 46()
  • You can also hide the hour to show just minute(+seconds): (6)08

Date (10-day weeks)

The UI shows a simple date line using 10-day weeks (UTC-based):

• Format: YYYY(WW.D) where week and day are both zero-indexed
• WW is the week number (00–36)
• D is the day within the 10-day week (0–9, single digit)
• Examples: 2025(00.0) (Jan 1), 2025(35.6) (late December)

No month concept is used at present; the year length remains Gregorian (365/366 days).

Timezones and solar reference

The main clock is global and based on UTC (everyone sees the same decimal time at the same instant).

The converters include a UTC offset option so you can interpret an input wall time as "UTC+02:00", "UTC−05:00", etc. (This does not apply DST rules; it is a fixed offset.)

Midsun (solar noon)

The "midsun" helper is an approximation based on longitude only:

• Greenwich (0°) midsun is 12:00 UTC (approximately decimal hour 48)
• Shifts by 4 standard minutes per 1° longitude
  • east (+): earlier
  • west (−): later

Notes:

• This intentionally does not include the equation of time, latitude, or atmospheric refraction.

Run it locally

• Open index.html directly in your browser, or
• Serve the folder with any static server (recommended for module loading), for example:

python3 -m http.server 8000

Then visit http://localhost:8000.

Deploy to GitHub Pages

This repo is already laid out for Pages from the repository root:

• GitHub → Settings → Pages
• Source: "Deploy from a branch"
• Branch: main / / (root)

After it deploys, your site is served over HTTPS (important: browsers typically require HTTPS for geolocation).

Custom domain (numpti.com)

This repo includes a CNAME file for GitHub Pages. In GitHub:

• Go to Settings → Pages
• Set Custom domain to numpti.com
• Ensure Enforce HTTPS is enabled once the certificate is issued

You’ll also need to point your domain’s DNS to GitHub Pages (exact records depend on your DNS host).

Tests

npm test

Privacy

• Clicking "Use my location" uses browser geolocation to read your coordinates.
• The app stores only your longitude and display options in localStorage (in your browser).
• No data is sent to any server by this project.

License

MIT (see LICENSE).