Re: Leap-seconds, the epsilon perspective

2003-01-29 Thread Ken Pizzini
On Wed, Jan 29, 2003 at 12:33:48AM -0800, Steve Allen wrote: What for? Why should we (the people of the Earth) care about mean solar days? For some purposes, apparent solar time is important, but most of the time it's civil time that counts. Why should that be tied to mean solar days?

FITS and the crafting of standards

2003-01-29 Thread Steve Allen
On Tue 2003-01-28T16:31:03 -0700, Rob Seaman hath writ: oscillatory modes.) Just one more example (among many) is my long time participation in the FITS standards process. FITS is astronomy's universal data format, whose metadata standards rely explicitly on UTC. For the sake of further

Re: FITS and the crafting of standards

2003-01-29 Thread Roger Stapleton
Can I muddy the waters with some facts/evidence I have collected recently? (if your answer is no - then hit 'delete' now ;-) First where do I fit in this debate. I am the systems manager for the Astronomy group at St.Andrews University. We run a small observatory with 4 telescopes, a couple of

Re: Leap-seconds, the epsilon perspective

2003-01-29 Thread John Cowan
Steve Allen scripsit: Which is more important... for civil time to be counted in SI seconds? for civil time to track the rotation of earth smoothly? IMHO the former. Mark's alternative resembles the civil time solution adopted by the martian colonists in Kim Stanley

Re: What problems do leap seconds *really* create?

2003-01-29 Thread Markus Kuhn
John Cowan wrote on 2003-01-29 17:56 UTC: The problem is that they are not announced much in advance, and one needs to keep a list of them back to 1972 which grows quadratically in size. Is this a real problem? Who really needs to maintain a full list of leap seconds and for what application

Re: What problems do leap seconds *really* create?

2003-01-29 Thread John Cowan
William Thompson scripsit: Any application which seeks to calculate the difference in time between two events recorded in UTC time needs to know if there are any leap seconds between the start and stop time. For example, suppose you were studying solar flares, and analyzing some data taken

Re: What problems do leap seconds *really* create?

2003-01-29 Thread Rob Seaman
Those of us with a day job may be having a hard time keeping up with the messages as they arrive fast and furious :-) # The need for leap seconds is not caused by the secular slowdown # of Earth's rotation (which is less than 2 milliseconds per century) # but by irregular variations in this

Re: What problems do leap seconds *really* create?

2003-01-29 Thread Steve Allen
On Wed 2003-01-29T15:43:24 -0700, Rob Seaman hath writ: Please! Let's talk about ways to improve UTC and civil timekeeping. And let's take the appropriate amount of time to reach a decision - say - 40 or 50 years. In the mean time, let's pay attention to the real question, which is how to

Re: What problems do leap seconds *really* create?

2003-01-29 Thread Mark Calabretta
On Wed 2003/01/29 15:43:24 PDT, Rob Seaman wrote in a message to: [EMAIL PROTECTED] Basically we don't have leap seconds because the Earth's rotation is slowing down (by transfering angular momentum to the Moon). Rather, we have leap seconds because the Earth has *already* slowed down since