Delta 𝑇: Polynomial Approximation of Time Period 1620–2013

Table 1

Values of scaling factor 𝑘 with coefficients of the 4th degree polynomial.

Duration	𝑘	𝑎0	𝑎1	𝑎2	𝑎3	𝑎4	Max. err.
1620–1672	3.670	76.541	–253.532	695.901	–1256.982	627.152	0.5709
1673–1729	3.120	10.872	–40.744	236.890	–351.537	36.612	0.5989
1730–1797	2.495	13.480	13.075	8.635	–3.307	–128.294	0.5953
1798–1843	1.925	12.584	1.929	60.896	–1432.216	3129.071	0.4643
1844–1877	1.525	6.364	11.004	407.776	–4168.394	7561.686	0.5894
1878–1904	1.220	−5.058	−1.701	–46.403	–866.171	5917.585	0.5410
1905–1945	0.880	13.392	128.592	–279.165	–1282.050	4039.490	0.5495
1946–1989	0.455	30.782	34.348	46.452	1295.550	–3210.913	0.4279
1990–2013	0.115	55.281	91.248	87.202	–3092.565	8255.422	0.2477