Re: civil time = solar time
On Thu 2006-01-05T08:18:11 +0100, Poul-Henning Kamp hath echoed Rob: Which is why the longitude conference decided on a 1 hour quantum. No, they did not. The delegates gratuitously offered existing schemes (the US railroads being one touted long and hard by some guy named Allen) along with proposed schemes (one for Europe had zones on meridians spaced 10 time-minutes apart). All of those schemes were withdrawn after being entered into the official record. The reasoning was that their conference could not pretend to assert any authority over local civil time in any jurisdiction. Only the local civil authorities can decide what passes for local civil time. In the US the result of this will be seen this year as many embedded devices start making daylight time transitions on the wrong dates. I remain in awe of McCarthy's indication that predicting leap seconds might be acceptable over decade timescales. I remain in dismay that said point is moot for embedded devices, for the local civil authorities are more whimsical than the earth with larger amplitude deviations at less predictable intervals. -- Steve Allen [EMAIL PROTECTED]WGS-84 (GPS) UCO/Lick ObservatoryNatural Sciences II, Room 165Lat +36.99858 University of CaliforniaVoice: +1 831 459 3046 Lng -122.06014 Santa Cruz, CA 95064http://www.ucolick.org/~sla/ Hgt +250 m
Re: civil time = solar time
Rob Seaman wrote: I said: all parties must certainly agree that civil time (as we know it) IS mean solar time. Ed says: saying that it IS civil time is probably a bit strong. Probably a bit strong is not precisely a staunch denial. It's not meant to be a staunch denial. I'm mostly supporting your argument - just trying to tone down one aspect which I think is overstated to avoid giving rehetorical ammunition to those who see things otherwise. Ed.
Re: civil time = solar time
Rob Seaman said: Rather, the often repeated canard that civilians don't give a fig for the actual position of the sun in the sky implies that it is precisely apparent solar time that only queer ducks like astronomers care about. Mean solar time is what civilians DO care about. Only *very* *very* approximately. In the UK, sunset varies from about 15:30 to about 22:30 LCT. Sunrise isn't an event most people even care about (for me, it shifts from happens at work to happens before I get up on an annual basis but, during the winter, on a weekly basis as well). Provided that astronomical noon is between about 08:00 and 16:00, most people won't care. For unless they see the sky, But they can't, and that is why They know not if it's dark outside or light. -- Clive D.W. Feather | Work: [EMAIL PROTECTED] | Tel:+44 20 8495 6138 Internet Expert | Home: [EMAIL PROTECTED] | Fax:+44 870 051 9937 Demon Internet | WWW: http://www.davros.org | Mobile: +44 7973 377646 Thus plc||
Re: Longer leap second notice
John Cowan said: Barry gules and argent of seven and six,John Cowan on a canton azure fifty molets of the second. [EMAIL PROTECTED] --blazoning the U.S. flag http://www.ccil.org/~cowan You don't get odd numbers of barry. It's Gules, six bars argent. -- Clive D.W. Feather | Work: [EMAIL PROTECTED] | Tel:+44 20 8495 6138 Internet Expert | Home: [EMAIL PROTECTED] | Fax:+44 870 051 9937 Demon Internet | WWW: http://www.davros.org | Mobile: +44 7973 377646 Thus plc||
Re: civil time = solar time
Clive D.W. Feather wrote: Rob Seaman said: Rather, the often repeated canard that civilians don't give a fig for the actual position of the sun in the sky implies that it is precisely apparent solar time that only queer ducks like astronomers care about. Mean solar time is what civilians DO care about. Only *very* *very* approximately. In the UK, sunset varies from about 15:30 to about 22:30 LCT. Sunrise isn't an event most people even care about (for me, it shifts from happens at work to happens before I get up on an annual basis but, during the winter, on a weekly basis as well). Provided that astronomical noon is between about 08:00 and 16:00, most people won't care. People certainly seem to care in this country (USA). There's always a lot of discussion about it when shifting between standard and daylight savings time, and especially when discussing the date on which that switch should take place. The biggest effect that people seem to be worried about is whether the Sun will be up when children are going to school in the morning. Similarly, many people with small farms also have other jobs, and have to complete their chores in the morning before going off to work. To them it's very important what time the Sun comes up. I have this on good authority from one of my colleagues who is in just this situation. It's also figured in discussions about DST in the media. Finally, there's a very good reason why politicians spend so much time worrying about DST--there's a distinct impact on the economy, especially in terms of energy use. People definitely care about the relationship between civilian time and apparent solar time. The amount of fiddling with the dates of DST to get it just right tells me that people care about apparent solar time to somewhat better than one hour accuracy. -- William Thompson NASA Goddard Space Flight Center Code 612.1 Greenbelt, MD 20771 USA 301-286-2040 [EMAIL PROTECTED]
