On 2009 Apr 14, at 03:19 , Tom Peters wrote:
Op 13-apr-2009, om 23:35 heeft Irv Bromberg het volgende geschreven:
I have added "Longest Solar Year" (grey) and "Shortest Solar Year" (black) curves to my equinoctial and solstitial year length plot, attached as a PDF (36 KB).
what is the timescale for your year lengths? UT or TDT?
the comment about increasing day length suggests that you express the year length in UT. However then the curves become very dependent on the exact expression you use for UT. Also I think that we cannot extrapolate the evolution of UT that far outside the interval of the historical records from -700 to +2000. Otherwise a very neat graph
Irv replies:
Thanks. I have contracted the year range of the graph (resulting also in a narrower mean year range), but I do really want to show the two present-era stable northward equinoctial year and north solstitial year, so the year range remains substantially wider than Tom's suggestion. It would be nice to indicate the extrapolated areas somehow, and that should be done on any chart that shows mean solar time or UT for the future or the remote past. The revised plot is now posted with the revised discussion at:
-- Irv Bromberg, Toronto, Canada
