On 2019-07-26 22:49, Steve Allen wrote:
On Fri 2019-07-26T23:16:08-0400 David Patte hath writ:
For my products I use an algorithm (Meeus; Astronomical Algorithms 1998) to 'predict' deltaT into the future. Does anyone have a good source for a more recent algorithm that takes into account IERS values since 1998? at the moment we seem to be pretty close to "Matsakis parabolic" https://www.ucolick.org/~sla/leapsecs/year2100.html but there are no guarantees
We all know what a shock there was after the last break in regular leap second additions, and given short memories in popular development circles, expect similar reactions next year or whenever the next addition happens. Are there any sources providing pointers to explanations of recent changes in EOP parameters and their likely cause, or info about likely reasons for (rather than factors affecting) the current (and earlier) period(s) of reductions in dUT1 change? https://en.wikipedia.org/wiki/ΔT#References has an interesting comment: Stephenson, F. R. & Morrison, L.V. "Long-term fluctuations in the Earth's rotation: 700 BC to AD 1990". Philosophical Transactions of the Royal Society of London, Series A 351 (1995) 165-202. https://www.jstor.org/stable/54464. "Includes evidence that the 'growth' in Delta-T is being modified by an oscillation with a wavelength around 1500 years; if that is true, then during the next few centuries Delta-T values will increase more slowly than is envisaged." -- Take care. Thanks, Brian Inglis, Calgary, Alberta, Canada This email may be disturbing to some readers as it contains too much technical detail. Reader discretion is advised.