All spring scales (not balance scales) are affected by the gravity of the sun. This includes virtually all digital scales these days. If memory serves, all spring scales read high by 1 part per thousand at midnight and low by 1 part per thousand at noon. The effect on blue shift is proportional. Again if memory serves blue shift from GPS is 66 parts per trillion. The noon midnight shift is 1,000 times less or 66e-15. I don't have time to calculate these and the exact figures are left to the student as an exercise. Buy gold at noon and sell at midnight. You make almost $4 per ounce. Most dealers use digital spring scales. Do not confuse solar tidal effects with the above. Again if memory serves, the sun has one-third of the tidal effect of the moon. On Wed, Feb 1, 2023 at 1:49 PM Demetrios Matsakis via time-nuts <time-nuts@lists.febo.com> wrote: > > There have been papers published about why there is no noon/midnight effect, and some dispute by the theorists about the proper explanation for the lack of it. > > I can point you to N. Ashby and M. Weiss, 2013, “Why there is no noon-midnight shift in the GPS”, http://arXiv [gr-qc]:1307.6525,https://arxiv.org/abs/1307.6525 These authors, as brilliant as the ones they disagree with, state that past arguments appealing to the second-order doppler shift being cancelled by the gravitational gradient miss the fundamental ideas behind the principle of simultaneity. > > > On Jan 31, 2023, at 12:06 PM, Steve Allen via time-nuts <time-nuts@lists.febo.com> wrote: > > > > On Tue 2023-01-31T15:34:16+0100 Marek Doršic via time-nuts hath writ: > >> Anybody studied the influence of the Sun's gravity on clocks in GNSS satellites? > >> The field might change slightly by 40,000 km distance when the sat > >> is closer to the Sun than later on the opossite side of Earth. Is > >> this measurable on the clocks? > > > > IAU 2000 resolutions B1.3 and B1.5 codify the understanding of the > > spacetime transformations from the potentials and metric. > > > > https://www.iau.org/static/resolutions/IAU2000_French.pdf > > > > This particular effect is small, and I am not sure that the GPS clocks > > are stable enough to reveal it. > > > > -- > > Steve Allen <sla@ucolick.org> WGS-84 (GPS) > > UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 > > 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 > > Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m > > _______________________________________________ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe send an email to time-nuts-leave@lists.febo.com > > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

Hi CDMA is another area that nukes leapseconds. There are a number of military applications that would get really tangled if you put them in, they also run some sort of “not UTC” timescale. A few folks seem to run POSIX time on their Linux boxes …. Bob > On Feb 1, 2023, at 3:59 PM, Lux, Jim via time-nuts <time-nuts@lists.febo.com> wrote: > > On 2/1/23 9:19 AM, Steve Allen via time-nuts wrote: >> On Tue 2023-01-31T10:20:13-0800 Lux, Jim via time-nuts hath writ: >>> TAI please, not UTC with ickyness like leapseconds. And, yes, there are >>> people who use GMT (although they're really using UTC, they just call it >>> GMT). >> But UTC is the primary. UTC is the tail that wags the dog. >> TAI has no legal existence. UTC is the legal time scale most places. >> Only BIPM can make TAI, no national laboratory can make TAI. >> Most national labs are required by statue to make UTC, and from > >> those BIPM constructs TAI. > > But in a space application you want no leapseconds - In practice everyone runs a local clock, and then goes through gyrations to convert that into some recognized frame and epoch. > > > >> >> -- >> Steve Allen <sla@ucolick.org> WGS-84 (GPS) >> UCO/Lick Observatory--ISB 260 Natural Sciences II, Room 165 Lat +36.99855 >> 1156 High Street Voice: +1 831 459 3046 Lng -122.06015 >> Santa Cruz, CA 95064 https://www.ucolick.org/~sla/ Hgt +250 m >> _______________________________________________ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe send an email to time-nuts-leave@lists.febo.com >> > _______________________________________________ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe send an email to time-nuts-leave@lists.febo.com

Dear Steve, On Wednesday, 1 February 2023 18:19:31 CET Steve Allen via time-nuts wrote: > On Tue 2023-01-31T10:20:13-0800 Lux, Jim via time-nuts hath writ: > > TAI please, not UTC with ickyness like leapseconds. And, yes, there are > > people who use GMT (although they're really using UTC, they just call it > > GMT). > > But UTC is the primary. UTC is the tail that wags the dog. > TAI has no legal existence. UTC is the legal time scale most places. > Only BIPM can make TAI, no national laboratory can make TAI. > Most national labs are required by statue to make UTC, and from > those BIPM constructs TAI. It's actually bit more complicated: The time laboratories do make their own UTC(k) indeed and it's also correct that the time differences of UTC(k) and e.g. the GPS satellites are reported to BIPM. But what's also reported is the time difference of the individual atomic clocks (mostly H-masers nowadays) with respect to UTC(k) and all the deliberate tuning done to those clocks. So from the UTC(K)-UTC(GPS) data together with these clock-tunings and clock measurements the 'bare' times of each clock is calculated. Based on that data, clocks are evaluated for their stability and assigned a weight factor determining how much they contribute to the atomic time scale "EAL". This time scale is stable, but perhaps not accurate. EAL-seconds are then rescaled based on a second set of atomic clock that excel in accuracy (Optical lattice clocks, fountain clocks, ion clocks) but are limited in number, not always operational and have worse stability. This rescaling then gives TAI-seconds. From the TAI timescale UTC is then derived based on the eventual addition or subtraction of leap seconds and UTC-UTC(k) is then published along with the other data as Circular-T bulletin. So in summary: I agree with every one of your statements above, except TAI is not calculated from UTC nor UTC(k) but rather from the individual clocks directly. How each time-lab creates their UTC(k) from their clocks has no influence on TAI nor UTC. Cheers, Jürgen