Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Brooks Harris
On 2017-10-23 06:31 PM, Warner Losh wrote: On Mon, Oct 23, 2017 at 3:42 PM, Brooks Harris > wrote: On 2017-10-23 02:07 PM, Warner Losh wrote: Never has been really, but it was the objective for centuries. Local time is obviously a

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Warner Losh
On Mon, Oct 23, 2017 at 3:42 PM, Brooks Harris wrote: > On 2017-10-23 02:07 PM, Warner Losh wrote: > > Never has been really, but it was the objective for centuries. Local time > is obviously a gross approximation, but a very useful one. Before atomic > time, navigation time

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Brooks Harris
On 2017-10-23 02:07 PM, Warner Losh wrote: On Mon, Oct 23, 2017 at 11:37 AM, Brooks Harris > wrote: On 2017-10-23 09:58 AM, Rob Seaman wrote: Multiple timescales exist now for multiple purposes. Multiple timescales

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Richard Langley
"UT1 is an artificial construct of averaging local time as well, with the seasonal variations subtracted out." No, that is wrong. Perhaps you are thinking of the (defunct) time scale UT2. UT1 gives us the true orientation of the Earth in space as measured (now) directly by space geodetic

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Poul-Henning Kamp
In message <59ee28f3.60...@edlmax.com>, Brooks Harris writes: > To me, the frustrating thing about the discussion at ITU and elsewhere > is the apparent outright refusal to consider a "second timescale". It is > considered and then dismissed out of hand in: The reason is very simple:

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Warner Losh
On Mon, Oct 23, 2017 at 11:37 AM, Brooks Harris wrote: > On 2017-10-23 09:58 AM, Rob Seaman wrote: > >> Multiple timescales exist now for multiple purposes. Multiple timescales >> will exist under all scenarios. Debasing Universal Time is not a >> solution to any "real world"

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread GERRY ASHTON
> On October 23, 2017 at 1:37 PM Brooks Harris wrote, in > part: > > The irreconcilable difficulty arises from UTC being a modification of > the Gregorian calendar algorithm. The world (mostly) uses Gregorian, but > then along comes this unpredictable and irregular Leap

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Brooks Harris
On 2017-10-23 09:58 AM, Rob Seaman wrote: Multiple timescales exist now for multiple purposes. Multiple timescales will exist under all scenarios. Debasing Universal Time is not a solution to any "real world" problem. If you want a new timescale, define a NEW timescale. Indeed. To me, the

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Warner Losh
On Mon, Oct 23, 2017 at 9:00 AM, Poul-Henning Kamp wrote: > > > > By that logic one should avoid intervals spanning the end of February > > because of leap days, and avoid any periods in the spring or fall (in > > either hemisphere) that might span local DST

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Warner Losh
On Mon, Oct 23, 2017 at 7:28 AM, John Sauter < john_sau...@systemeyescomputerstore.com> wrote: > On Sun, 2017-10-22 at 23:46 -0600, Warner Losh wrote: > > > > > > On Sun, Oct 22, 2017 at 11:02 PM, John Sauter > computerstore.com> wrote: > > > On Sun, 2017-10-22 at 17:53

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Poul-Henning Kamp
> By that logic one should avoid intervals spanning the end of February > because of leap days, and avoid any periods in the spring or fall (in > either hemisphere) that might span local DST transitions, [...] That is balderdash, and you know it: We know exactly when leap-days happen,

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Rob Seaman
Well, there's an experiment for the next leap second. Watch the 10 MHz and PPS coming out of a GPSDO with an oscilloscope set to trigger at midnight UTC. I think our Rigol accepts an external trigger. The Meinberg can generate one at 23:59:59. Two second window. After a couple of decades of this

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Tom Van Baak
> By that logic, one should avoid any interval that includes June 30 or > December 31, since such an interval might include a leap second. John, Right. Exactly. Which is why some systems that need to keep time reliably, or that integrate frequency to get time, avoid leap seconds altogether.

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread Rob Seaman
See below. On 10/23/17 6:28 AM, John Sauter wrote: > On Sun, 2017-10-22 at 23:46 -0600, Warner Losh wrote: >> >> On Sun, Oct 22, 2017 at 11:02 PM, John Sauter > computerstore.com> wrote: >>> On Sun, 2017-10-22 at 17:53 -0700, Steve Allen wrote: The BIPM has

Re: [LEAPSECS] leap second roundup 2017

2017-10-23 Thread John Sauter
On Sun, 2017-10-22 at 23:46 -0600, Warner Losh wrote: > > > On Sun, Oct 22, 2017 at 11:02 PM, John Sauter computerstore.com> wrote: > > On Sun, 2017-10-22 at 17:53 -0700, Steve Allen wrote: > > > > > > The BIPM has contributed > > > CGPM draft Resolution "On the