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Conventional clocks can be misleading

@Jackel: I know that when I did shift work I felt crummy all the time, crummier than before or after. But other factors added to the schedule disruption, so I'm unable to say how much of my diificulty was caused by adjusting to odd schedules. Working as an nighttime radio announcer, shutting down the transmitter in the early morning hours, gave me no trouble... though bicycling home from the station through miles of rough neighborhoods wasn't exactly fun either.

To sum up, I think (on little besides personal evidence) that schedule disruptions might cause adverse effects in some people. There's evidence to the contrary -- some people appear to adjust without much trouble to schedules that I find bizarre, such as eighteen-hour days for a submarine crew. Of therapies I know nothing, so have no opinion.

You can find the local times you want for yourself. Just google local solar time and you should find some useful calculators, as well as explanations and diagrams and whatnot.

[edit] The answer you got from richardm was local time. Local MEAN solar time. Civil timekeeping is based on the mean sun.
 
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Hi Roger.

Not so much selling my ideas about clocks as exploring overlooked aspects of time, as well as of course looking to see who might be interested in using a free clock that hieroglyphically displays the passage of day and the passage of night for a given longitude and latitude mapped to a conventional representation of time?

And the moniker is Jackel.

BTW, thanks for the luck part and also for the link. It brings back fond memeories of the distinction between day and night, da and nyet, der and nicht -- and of course Yalel's "coming towards" and "going away from". :-)

roger said:
Hi Yale.

Back here trying to sell us on your ideas on clocks, I see.

Good luck!

http://www.internationalskeptics.com/forums/showthread.php?t=50154
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I already use a free clock that doubles as a handy light source during daytime. With an inexpensive, backyard-based adapter it also eliminates the need for a wasteful electric clothes dryer.
 
Hi Meffy,

So what is the correct term for local, not mean time? I was of the apparently erroneous impression that "local time" meant "not mean" time. I.e, that, as contrasted with the standard time within a time zone, local meant "adjusted to the passage of the sun at some locality."

Meffy said:
@Jackel: I know that when I did shift work I felt crummy all the time, crummier than before or after. But other factors added to the schedule disruption, so I'm unable to say how much of my diificulty was caused by adjusting to odd schedules. Working as an nighttime radio announcer, shutting down the transmitter in the early morning hours, gave me no trouble... though bicycling home from the station through miles of rough neighborhoods wasn't exactly fun either.

To sum up, I think (on little besides personal evidence) that schedule disruptions might cause adverse effects in some people. There's evidence to the contrary -- some people appear to adjust without much trouble to schedules that I find bizarre, such as eighteen-hour days for a submarine crew. Of therapies I know nothing, so have no opinion.

You can find the local times you want for yourself. Just google local solar time and you should find some useful calculators, as well as explanations and diagrams and whatnot.

[edit] The answer you got from richardm was local time. Local MEAN solar time. Civil timekeeping is based on the mean sun.
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Mine works equally well in windowless cubicles and other such environs. Plus it equally well displays the passage of night as well as day. Yours doesn't.

OTOH, my clock cannot dry clothes nor light fires using a magnifying glass. So I guess yours wins! :-)

Meffy said:
I already use a free clock that doubles as a handy light source during daytime. With an inexpensive, backyard-based adapter it also eliminates the need for a wasteful electric clothes dryer.
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I don't enter windowless cubicles, and for the passage of the night I use other indicators similar to the daytime one but in other jurisdictions. :-)
 
Jackel said:
So what is the correct term for local, not mean time?
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I think "true solar time" is the right phrase. None of the words are optional. Note that local time can be mean or true -- this is not the same as the effect of a difference in longitude from the zonal center meridian. the mean versus true discrepancy is the effect of (or evidence showing) earth's orbital eccentricity.

[edit] In other words, mean time assumes the sun moves at a constant apparent angular rate along the ecliptic, but in fact the rate is non-uniform. Mechanical clocks run at a uniform rate. The equation of time corrects for this, or rather allows us to adjust clock time to time as measured by the progress of the sun across the sky, or vice versa. The amount of the sun-fast and sun-slow effect changes with latitude, not longitude, as is the case with the local-versus-zonal-standard difference.
 
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Meffy said:
Yah! That's it.

At the Science Museum of Virginia, not far from where I live, they made a giant analemmic sundial by marking the position on the parking lot of the shadow of the flagpole's ball finial at noon every sunny day for a year, then painting the curve and markers. An inexpensive and directly engaging exhibit.
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A building here in KC had a big sundial installed on the outside of it when it was built (during the winter). In the middle of summer a second set of numbers showed up. Apparently they had gotten so many calls that their "clock" was off by an hour they had to add a second set of numbers for daylight savings time.
 
Jackel said:
So what is the correct term for local, not mean time? I was of the apparently erroneous impression that "local time" meant "not mean" time. I.e, that, as contrasted with the standard time within a time zone, local meant "adjusted to the passage of the sun at some locality."
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Local time is whatever the time the locals have agreed it is. noon occurs at the same instant in time in both Kansas City and St. Louis but the sun is directly overhead in STL before it is in KC.

http://time.gov/
 
If you live in a location with mountains to one side - east or west, then the time of local sunrise and sunset can become significantly skewed.

I think noon occurs when the sun reaches it's highest elevation - this may not occur midway between sunrise and sunset unless you have a level horizon.
 
I combined the two identical topics into one thread.
Replying to this modbox in thread will be off topic  Posted By: Lisa Simpson
 
Your interesting point seems to be in conflict with the standard computations of local sunrise and local sunset which produce time-of-local-sunrise/time-of-local-sunset results found at a variety of websites.


ceptimus said:
If you live in a location with mountains to one side - east or west, then the time of local sunrise and sunset can become significantly skewed.

I think noon occurs when the sun reaches it's highest elevation - this may not occur midway between sunrise and sunset unless you have a level horizon.
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The definitions of civil/astronomical sunrise and sunset are based on an ideal horizon with no hills, mountains, or trees to deal with. When you live in the mountains, the sun often becomes hidden before the sky goes dark (or doesn't appear until hours after the sky has brightened) due to valleys being in the shadows of the mountains they lie between. It's an odd kind of anti-twilight that I find disorienting; I don't like having to guess where the sun is behind a massif.

Midday is when the sun transits the sky's north-south meridian, whatever your real local horizon is shaped like.
 
kevin said:
Local time is whatever the time the locals have agreed it is. noon occurs at the same instant in time in both Kansas City and St. Louis but the sun is directly overhead in STL before it is in KC.

http://time.gov/
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Exactly. Even if it was set correctly for your time zone, the time zones are awfully wide. To make it totally accurate you would need a separate time zone for each possible position (longitude). Wouldn't that be fun!

LLH
 
That's exactly the situation that used to obtain in the early days of U.S. railroading, when travelling long distances fast became a reality. Conductors used to spend a lot of effort setting those big pocketwatches to the right time for the next stop. Time zones were the solution for this and other commercially messy aspects of local time.
 
Beady said:
As a practical matter, the time most people (in the States) live by is set by the phone company, which is usually ~4 minutes off from "official" atomic colock time.
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Really? Kinda sloppy but maybe not too unreasonable. Anything tighter than "a few minutes" seems silly for everyday timekeeping.

Lots of computers are equipped to sync to time servers. But I couldn't guess how many are configured right so they do it automatically at a sane interval. Before getting our home net connected to the big ol' Internet, I used to set computer clocks via CHU or WWV on shortwave. Yeah: picky picky picky.
 
Meffy said:
That's exactly the situation that used to obtain in the early days of U.S. railroading, when travelling long distances fast became a reality. Conductors used to spend a lot of effort setting those big pocketwatches to the right time for the next stop. Time zones were the solution for this and other commercially messy aspects of local time.
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The same problem was encountered when the first train started running in the Netherlands in 1839, between Amsterdam and Haarlem. Even though the two cities are less than twenty kilometers apart, the difference in mean times was enough to make things awkward.
 
It gets worse -- even nowadays, unless something's changed in the past few years, Amtrak passenger trains en route when the US switches from Daylight Time back to Standard Time have to stop for an hour while the clock catches back up so the trains don't travel during two different "12:20am"s (or whatever) on the same date. A safety measure but it sure seems bizarre to me.

[edit] I don't know whether freights or non-Amtrak passenger lines (are there any left besides local scenics and commuters?) adhere to this practice.
 
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Beady said:
As a practical matter, the time most people (in the States) live by is set by the phone company, which is usually ~4 minutes off from "official" atomic colock time.
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I don't understand. What does the phone company have to do with the time people live by?

Do they keep the wrong time on purpose, or do they just not care?
 
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