There are two independent timekeeping authorities in the US, the NIST and the Navy, which maintain the official civil and military time respectively. By policy the civil and military time are synchronized, and the precise offset between civil and military time is monitored by the NIST as a form of quality assurance. The offset between the two is generally less than the error in the comparison method.
The Navy offers a similar online time service although it is clearly far less developed from a design perspective (https://www.usno.navy.mil/USNO/time/display-clocks/simpletim...). However, what's perhaps more useful is that the Navy continues to offer a telephone time service (202-762-1401) while NIST does not. Additionally, the GPS time, while operated by the Air Force, is precisely synchronized to the Navy time plus or minus a known offset (due to the decision to no longer apply leap seconds to the GPS constellation to avoid leap-second-related problems).
There is some history here. The NIST is interested in timekeeping from a metrological perspective since it is important to many commercial and scientific pursuits. The Navy, on the other hand, has long been interested in accurate timekeeping because it is required for celestial navigation. The transit telescope maintained at the Naval Observatory comes from the legacy of the Naval Observatory as a tool to correctly adjust the clocks used by ships at sea for navigation. Similarly, many of the most significant advances in mechanical timekeeping were spurred by the need for compact and reliable clocks for use at sea.
The Navy operates master clock equipment at Schriever AFB for closer proximity to the NIST equipment at Boulder, but the primary means of comparison of the two time bases is by observing the GPS time. Because of the simplicity and low cost of GPS time sources, GPS is as ubiquitous for time measurement as it is for navigation.
One interesting thing about Schriever AFB and its critical role in the GPS system... It's one of the few US military facilities in the 48 states that has a true double perimeter fence system around it. Take a look at it from google earth in satellite/aerial view. The security around it is very nearly as high as the Pantex plant in Texas (nuclear bomb assembly/disassembly facility).
Thank you very much; this is a very detailed post that covers several things I was wholly unaware of. One minor gripe:
> However, what's perhaps more useful is that the Navy continues to offer a telephone time service (202-762-1401) while NIST does not.
NIST also has a phone # service, but regardless, I'm struggling to think of a scenario where dialing a phone # would be more useful and/or accurate than any other method. I haven't called a number to set my clock since the '90s.
If the history of timekeeping for navigation sounds interesting, check out the book (and movie) “Longitude” by Dava Sobel. It’s an incredible and largely-forgotten story.
So if we're using the Nautical Almanac for navigation purposes,does it matter if we use NIST or Navy? Or is the synchronization very close? Also, where can I learn more? In the sailing community these questions come up, believe it or not.
The phone number doesn't work. Just tried calling it on my cell phone. I'm just getting a constant ringing with nothing picking up I'm very disappointed.
I am curious, when did the decision to make GPS not follow leap seconds occur? had you asked me before I read your comment, I would have said that it doesn't honor leap seconds and never has.
I can't comment on accessibility or responsiveness or what have you, but this is a wonderful display. Strong, clear delineations without being too bright or garish, and densely packs a bunch of information together without losing clarity or concision. Love it.
It's brilliant. And the front-end code, though not at all complicated, is clean and easy to understand. I can't speak for code quality, though.
NIST published an update to their About page for time.gov mid-week (https://www.nist.gov/pml/time-and-frequency-division/about-t... ); the only reason I know it was updated today or might've been late last night is because I used the old time.gov to set a watch the day before, and when I opened the tab today, the clock read:
aN:aN:aN
---
The nice part is that save for the custom web analytics code from digitalgov.gov as well as jquery, it's not minimized.
It looks like it was designed to fit perfectly above the fold on the screen, but then some manager (to put it mildly) came along and made them insert a useless grey bar at the top, pushing everything else down. Nothing a little "Block element..." can't fix, though.
I remember using time.gov about 17 years ago. It was "worse" back then: the home page had two buttons: one that displayed a static time in HTML, the other that displayed a Flash or Java element where the seconds ticked. (Worse compared to today, back then it was good for the time and I appreciated the resource.)
Great job to those of you working on this website! The update looks amazing, and I'm sure I will continue using it for years to come!
That's an amazing improvement, but I'm already nostalgic for the old design. Next you're going to tell me they've upgraded the Space Jam website.
Tangentially, I find myself using https://time.is/ a lot, check it out if you frequently need to check time in another city or verify your clock is synced.
I used to use time.is, but recently it's gotten more and more ads. Now, this new version of time.gov has the feature that compares device time to correct time, so I think I'm going to switch over.
Maybe a silly question, but how can they reliably detect and display the error between my system time and the actual time? I would think there'd be some latency introduced while the page is being loaded/drawn, and by the JavaScript code that's displaying/changing the time, among others.
While I used to use this years ago managing servers I recently pulled up the old version again helping some admins in my org debug why the 2factor Authenticator apps weren’t working for signon.
Both server and client must have synced time.
I validated my phone and desktop’s time using time.gov when the admins claimed that their server was right and my clients were off.
I thought it was kind of funny they would claim their time was accurate without checking it. Also funny that their server and local ntp would be off.
But time.gov saved the day by providing an always available, easy to use standard.
I can't believe all the seconds on that page aren't synchronized. Or at least on my tablet they aren't! They're flipping at slightly different moments. Should have had one timer event firing to change every element at the same tick.
They are all updated in the same JavaScript function.
However each clock is updated in a seperate call to .innerHTML. This means the DOM is updated seperately for each clock instead of just once for all the clocks.
So depending on how eager your browser is about doing layouts, I could imagine different clocks updating on different frames to be a possibility.
I thought that was happening at first on my fast desktop, but it seemed to be to be an optical illusion the more I looked at it. I’d probably have to set some breakpoints or something to verify, but it’s Friday night...
How does this work if your time is really far off? The actual time is served over HTTPS (and the server doesn't even listen on port 80), so if your system time is so far off that it's beyond the validity range of the certificate, your browser won't let the site load. Then you won't be able to determine the time, and fix your computer.
This feels like the one website ever that needs to be served over HTTP ;)
In fact, considering it's from NIST, there's a stunning lack of precision in the map. The controversial Florida timezone split (2000 elections) isn't reflected here either, and the map itself is largely rounded without considering individual locales.
For a while, Time.gov was one of the poster children for Lazlo (https://en.wikipedia.org/wiki/OpenLaszlo), one of the more interesting cross platform toolsets back in the day (akin to Haxe nowadays). You can see the LZW (lzx) files in older versions of the site in Archive.org Wayback (2007 or so onward). The team translated their purely Java portion into Lazlo then cross compiled into swf for Flash. So, it went from CGI (perl) to Java to Flash to HTML (still via Laszlo) to a few revisions here and there to work around browser changes to finally this latest revamp. See some background in https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=50644 from 2007.
I looked into it and it turns out that on Firefox Developer Edition (v73.0b12 64-bit) returns an incorrect value for Date.getTimezoneOffset() (0 instead of the expected -60). I'm not sure if it's a bug or an anti-tracking/privacy "feature".
It's probably because you have Firefox Developer Edition. Do private windows always open at the same, 4:3 window size? If so, that sounds like the resistFingerprinting about:config entry.
[+] [-] jcrawfordor|6 years ago|reply
The Navy offers a similar online time service although it is clearly far less developed from a design perspective (https://www.usno.navy.mil/USNO/time/display-clocks/simpletim...). However, what's perhaps more useful is that the Navy continues to offer a telephone time service (202-762-1401) while NIST does not. Additionally, the GPS time, while operated by the Air Force, is precisely synchronized to the Navy time plus or minus a known offset (due to the decision to no longer apply leap seconds to the GPS constellation to avoid leap-second-related problems).
There is some history here. The NIST is interested in timekeeping from a metrological perspective since it is important to many commercial and scientific pursuits. The Navy, on the other hand, has long been interested in accurate timekeeping because it is required for celestial navigation. The transit telescope maintained at the Naval Observatory comes from the legacy of the Naval Observatory as a tool to correctly adjust the clocks used by ships at sea for navigation. Similarly, many of the most significant advances in mechanical timekeeping were spurred by the need for compact and reliable clocks for use at sea.
The Navy operates master clock equipment at Schriever AFB for closer proximity to the NIST equipment at Boulder, but the primary means of comparison of the two time bases is by observing the GPS time. Because of the simplicity and low cost of GPS time sources, GPS is as ubiquitous for time measurement as it is for navigation.
[+] [-] walrus01|6 years ago|reply
[+] [-] dlgeek|6 years ago|reply
https://www.nist.gov/pml/time-and-frequency-division/radio-s...
(303) 499-7111 - WWV (Colorado)
(808) 335-4363 - WWVH (Hawaii)
[+] [-] fyrabanks|6 years ago|reply
> However, what's perhaps more useful is that the Navy continues to offer a telephone time service (202-762-1401) while NIST does not.
NIST also has a phone # service, but regardless, I'm struggling to think of a scenario where dialing a phone # would be more useful and/or accurate than any other method. I haven't called a number to set my clock since the '90s.
[+] [-] wglb|6 years ago|reply
But on this page https://www.nist.gov/pml/time-and-frequency-division/radio-s... NIST shows a working phone number...
[+] [-] js2|6 years ago|reply
https://en.wikipedia.org/wiki/WWV_(radio_station)
https://www.nist.gov/pml/time-and-frequency-division/radio-s...
When I was a kid my dad had built a Heathkit multiband radio receiver[1] and we used that station to set our clocks at home.
1. https://commons.wikimedia.org/wiki/File:Vintage_Heathkit_16-...
[+] [-] dfee|6 years ago|reply
[+] [-] guscost|6 years ago|reply
[+] [-] dhimes|6 years ago|reply
[+] [-] hamandcheese|6 years ago|reply
[+] [-] Something1234|6 years ago|reply
[+] [-] euler_angles|6 years ago|reply
[+] [-] anonymousiam|6 years ago|reply
[+] [-] Amorymeltzer|6 years ago|reply
[+] [-] eganist|6 years ago|reply
NIST published an update to their About page for time.gov mid-week (https://www.nist.gov/pml/time-and-frequency-division/about-t... ); the only reason I know it was updated today or might've been late last night is because I used the old time.gov to set a watch the day before, and when I opened the tab today, the clock read:
---The nice part is that save for the custom web analytics code from digitalgov.gov as well as jquery, it's not minimized.
[+] [-] chrisseaton|6 years ago|reply
[+] [-] unknown|6 years ago|reply
[deleted]
[+] [-] neurobro|6 years ago|reply
[+] [-] danso|6 years ago|reply
[+] [-] RandomBacon|6 years ago|reply
Great job to those of you working on this website! The update looks amazing, and I'm sure I will continue using it for years to come!
[+] [-] xwowsersx|6 years ago|reply
[+] [-] ebg13|6 years ago|reply
[+] [-] csande17|6 years ago|reply
[+] [-] hanspeter|6 years ago|reply
[+] [-] sciurus|6 years ago|reply
Tangentially, I find myself using https://time.is/ a lot, check it out if you frequently need to check time in another city or verify your clock is synced.
[+] [-] 333c|6 years ago|reply
[+] [-] whitehouse3|6 years ago|reply
I only wish it had more date display options: day number and ISO8601 Week Number.
[+] [-] mycall|6 years ago|reply
[+] [-] thedance|6 years ago|reply
ETA: my local linux box by contrast is off by 1ms.
[+] [-] vector_spaces|6 years ago|reply
[+] [-] twright|6 years ago|reply
[+] [-] petarb|6 years ago|reply
https://i.imgur.com/703v1cC.jpg
[+] [-] eganist|6 years ago|reply
https://i.imgur.com/dFrM24l.jpg
Edit: holy cow that screenshot became dated very quickly. Map was updated to fix Florida and Texas; new screenshot as of 9:35 UTC-5:
https://i.imgur.com/9ynIz5G.jpg
[+] [-] prepend|6 years ago|reply
Both server and client must have synced time.
I validated my phone and desktop’s time using time.gov when the admins claimed that their server was right and my clients were off.
I thought it was kind of funny they would claim their time was accurate without checking it. Also funny that their server and local ntp would be off.
But time.gov saved the day by providing an always available, easy to use standard.
[+] [-] russellbeattie|6 years ago|reply
[+] [-] missblit|6 years ago|reply
However each clock is updated in a seperate call to .innerHTML. This means the DOM is updated seperately for each clock instead of just once for all the clocks.
So depending on how eager your browser is about doing layouts, I could imagine different clocks updating on different frames to be a possibility.
[+] [-] reilly3000|6 years ago|reply
[+] [-] afterburner|6 years ago|reply
[+] [-] jrockway|6 years ago|reply
This feels like the one website ever that needs to be served over HTTP ;)
[+] [-] whiddershins|6 years ago|reply
The Navajo Nation Reservation is on a different time zone than the state it is mostly inside.
But the Hopi Reservation is entirely contained within the Navajo, and is on a different time zone.
When we drove through that region my phone just freaked out, switching times back and forth arbitrarily.
And the hotel had three clocks in the lobby for clarification.
[+] [-] saltedonion|6 years ago|reply
[+] [-] dtparr|6 years ago|reply
Edit: fixed now. Quick work for a Friday night!
[+] [-] Mountain_Skies|6 years ago|reply
Hello NIST employee watching this thread. Nice quick turnaround!
[+] [-] eganist|6 years ago|reply
https://en.wikipedia.org/wiki/Time_in_the_United_States
In fact, considering it's from NIST, there's a stunning lack of precision in the map. The controversial Florida timezone split (2000 elections) isn't reflected here either, and the map itself is largely rounded without considering individual locales.
edit: fixed! Nice!
[+] [-] afterburner|6 years ago|reply
[+] [-] jumpinalake|6 years ago|reply
[+] [-] ourmandave|6 years ago|reply
It also showed a world map and where the sun was currently shining.
I only know it used to be one of the first results on googling "current time".
[+] [-] mwexler|6 years ago|reply
[+] [-] po1nter|6 years ago|reply
I looked into it and it turns out that on Firefox Developer Edition (v73.0b12 64-bit) returns an incorrect value for Date.getTimezoneOffset() (0 instead of the expected -60). I'm not sure if it's a bug or an anti-tracking/privacy "feature".
[+] [-] wizzwizz4|6 years ago|reply