3 ms·

Worth emphasizing that decimal time is not just historical curiosity and fringe idea, especially the astronomical community uses decimal time fairly regularly,

by zokier 3y ago

Worth emphasizing that decimal time is not just historical curiosity and fringe idea, especially the astronomical community uses decimal time fairly regularly, various "julian date" systems attest that. https://en.wikipedia.org/wiki/Julian_day https://en.wikipedia.org/wiki/Julian_day

jhoechtl 3y ago
not to forget that an astronomoical day has no 24 hours https://en.wikipedia.org/wiki/Sidereal_time https://en.wikipedia.org/wiki/Sidereal_time
akira2501 3y ago
The USPS used it when I worked there in the 90s. They used 24 hour days with 100 ticks of 36 seconds per each hour. The time clocks operated in this format. Which was interesting, until you also realized, they expected you to clock in precisely at the start of your shift, giving you a 36 second window to do it in. On the first day I was wondering why there were so many time clocks for the size of the office and then I witnessed the shift change "stampede" that this policy incidentally created.
- niklasrde 3y ago
  How does the time system relate to the clock-in expectation? Otherwise you would have 60 seconds to do it in, which feels like not much more time?
- aredox 3y ago
  Oh, interesting! Is there an historical explanation somewhere on how and why they adopted this system?
- crazygringo 3y ago
  What happened if you missed it and clocked in the following "minute"?
  - akira2501 3y ago
    If I recall correctly, for up to 5 "ticks" you could make it up at the end of your shift, for anything more you got reported. It was a union job and so there were a lot of little "parsimonious" rules like this. To answer the other question at the same time, in the 90s, was most shops that used an analog time clock would only advance the stamped time every 5 minutes. So, if you clocked in at 8:04, it would still punch 8:00 on your card. So, it was notable to me at the time that they had clocks with a finer grain of accuracy that fed into their computers immediately, and they actually cared about the "slop" involved in time keeping.
    - crazygringo 3y ago
      Thanks! Very interesting.
tgv 3y ago
A decimal fraction is not the same as decimal time. There may be a simple conversion (* 1000), but the conversion to 24hr time is almost as simple. The problem with decimal time is that it is a proposal for people to use, and that it solves no problems at an immense conversion cost.
gmiller123456 3y ago
As someone who's done quite a bit of astronomy programming, I can say the Julian Date is not really a replacement for decimal time. The Julian Date really isn't much different than a Unix Timestamp (in fact, you can convert between the two quite easily: jd = UnixTimestamp / 86400 + 2440587.5). They are both good for punching in to algorithms, but not good for direct use by people.

by zokier 3y ago

jhoechtl 3y ago

not to forget that an astronomoical day has no 24 hours https://en.wikipedia.org/wiki/Sidereal_time https://en.wikipedia.org/wiki/Sidereal_time

akira2501 3y ago

The USPS used it when I worked there in the 90s. They used 24 hour days with 100 ticks of 36 seconds per each hour. The time clocks operated in this format. Which was interesting, until you also realized, they expected you to clock in precisely at the start of your shift, giving you a 36 second window to do it in. On the first day I was wondering why there were so many time clocks for the size of the office and then I witnessed the shift change "stampede" that this policy incidentally created.

niklasrde 3y ago
How does the time system relate to the clock-in expectation? Otherwise you would have 60 seconds to do it in, which feels like not much more time?
aredox 3y ago
Oh, interesting! Is there an historical explanation somewhere on how and why they adopted this system?
crazygringo 3y ago
What happened if you missed it and clocked in the following "minute"?
- akira2501 3y ago
  If I recall correctly, for up to 5 "ticks" you could make it up at the end of your shift, for anything more you got reported. It was a union job and so there were a lot of little "parsimonious" rules like this. To answer the other question at the same time, in the 90s, was most shops that used an analog time clock would only advance the stamped time every 5 minutes. So, if you clocked in at 8:04, it would still punch 8:00 on your card. So, it was notable to me at the time that they had clocks with a finer grain of accuracy that fed into their computers immediately, and they actually cared about the "slop" involved in time keeping.
  - crazygringo 3y ago
    Thanks! Very interesting.

tgv 3y ago

A decimal fraction is not the same as decimal time. There may be a simple conversion (* 1000), but the conversion to 24hr time is almost as simple. The problem with decimal time is that it is a proposal for people to use, and that it solves no problems at an immense conversion cost.

gmiller123456 3y ago

As someone who's done quite a bit of astronomy programming, I can say the Julian Date is not really a replacement for decimal time. The Julian Date really isn't much different than a Unix Timestamp (in fact, you can convert between the two quite easily: jd = UnixTimestamp / 86400 + 2440587.5). They are both good for punching in to algorithms, but not good for direct use by people.