71–80 of 89 posts
Not many people know NIST offers a cookbook for perfectly calibrated food https://www.nist.gov/pml/owm/metric-si/metric-kitchen/metric...
Also known as an ordinary recipe everywhere else. Well, recipes do often use measurements like teaspoons and cups, but they have straightforward metric equivalents - a teaspoon being 5mL and a cup 250mL.
Long before most of you were born there was a special number you could call to get the time here in the USA. It would give you a localized time every 10 seconds. It was considered an authoritative value, but I knew that normal analog clocks drifted a fair amount, and I was fascinated by the Time voice. There was also a special number to dial that was called Information. When I was about 12, I suddenly thought that’s…
Plus you can hear two signals from NIST themselves:
(303) 499-7111 - WWV (John Doyle)
(808) 335-4363 - WWVH (Jane Barbe) - in Hawaii, might cost extra to call depending on plan
And there are these two offered by US Naval Observatory in Washington
(202) 762-1069
(202) 762-1401
Plenty more out there if you do some Googling.
Long before most of you were born there was a special number you could call to get the time here in the USA. It would give you a localized time every 10 seconds. It was considered an authoritative value, but I knew that normal analog clocks drifted a fair amount, and I was fascinated by the Time voice. There was also a special number to dial that was called Information. When I was about 12, I suddenly thought that’s…
Here in Australia we had a number that gave you the time called 'George the talking clock'. https://1194online.com
https://se.au/notes/george-the-talking-clock-lives-on/
Number Region
02 8403 1194 Sydney/Melbourne/Canberra
08 7078 7794 Adelaide
07 3667 9594 Brisbane
08 7918 0808 Darwin
08 6244 3294 Perth
Earlier quoted context omitted.
Cost, size, weight, and power are definitely things that can be improved on. The atomic clocks you can buy for a lab are big 3U boxes but shrinking it down to something portable is the future. I actually work with one of those chip scale atomic clocks. The goal is to put it in space. If you need precise timing in space, the current state is to lock to a GPS reference clock (just for timing, don't care about position)…
Where are you getting GPS receivers that work in space?
https://gdmissionsystems.com/communications/spaceborne-commu...
Earlier quoted context omitted.
That's brilliant. Sometimes talking to real humans is great. It reminds me of two things. When I was a child I was given a postage stamp and wrote a letter to "Wallace and Gromit Ltd" and posted it. Remarkably, I got a reply from Aardman Animations with a card signed by Nick Park himself. Someone at Royal Mail obviously understood and looked up the real address of the studio. Later as a teen I noticed the clock on ou…
I like that both 0:00 and 24:00 exist. If you say "midnight, August 12", do you mean at the start or the end of the day? There might be a convention, but I don't know it so others probably don't either. With 0:00 and 24:00 and a date, you can disambiguate a time precisely.
The only instant that could exist would be 24:00:00. If you told me it was 24:00:05, I'd say poppycock - that's tomorrow, 00:00:05 instead.
Earlier quoted context omitted.
Symmetricom (now owned by Microchip) released the first Chip Scale Atomic Clocks in 2011. It probably took some time for them to become available to watch designers and for them to be integrated into watch designs. https://www.nist.gov/noac/success-story-chip-scale-atomic-cl... I'm guessing the watches sold poorly and the chip packages are still large compared to a watch movement, so no new designs.
Sadly, no major miniaturization breakthroughs since. And those CSACs still eat up a lot of power (as do good OCXOs), making them rough for battery powered wearables.
I recently bought my first not-super-cheap watch, and found out that all around the world there radio stations which broadcast the atomic clock time that a lot of clocks/watches listen to. After setting the time zone (I guess this also changes the frequency that it listens on) it starts to sync itself using that signal. It is also solar-charging - so this basically means that I never have to touch it. Although it's a…
What, Exactly, Is a Clock? To understand atomic time, we must first understand something about clocks. A clock is, at its core, a marriage of two components: a mechanism that oscillates, or ticks with a steady beat, and a device that counts those beats and displays the time Yeah but more deeply time is a property of the universe that the clock including atomic clocks are tracking. Kant said it is 'schema' i.e. withou…
> Yeah but more deeply time is a property of the universe that the clock including atomic clocks are tracking. I'll quote Einstein who said "time is what the clock says".
Earlier quoted context omitted.
Where are you getting GPS receivers that work in space?
Probably one of the numerous companies making qualified receivers? E.g. [0]. There's even a published table comparing basically all of them [1]. [0] https://www.aac-clyde.space/what-we-do/space-products-compon... [1] https://www.mdpi.com/1424-8220/23/17/7648#app1-sensors-23-07...