↑ IERS Rapid Service/Prediction Center (c. 1986). Historic Delta T and LOD. Source attributed data to McCarthy and Babcock (1986). Retrieved December 2009.
↑ Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac, Nautical Almanac Offices of UK and US (1961), at pp. 9 and 71.
↑ See G M Clemence's proposal of 1948, contained in his paper: "On the System of Astronomical Constants", Astronomical Journal (1948) vol.53 (6), issue #1170, pp 169–179; also G M Clemence (1971), "The Concept of Ephemeris Time", in Journal for the History of Astronomy v2 (1971), pp. 73–79 (giving details of the genesis and adoption of the ephemeris time proposal); also article Ephemeris time and references therein.
↑ See Newcomb's Tables of the Sun (Washington, 1895), Introduction, I. Basis of the Tables, pp. 9 and 20, citing time units of Greenwich Mean Noon, Greenwich Mean Time, and mean solar day: and W de Sitter, on p. 38 of Bulletin of the Astronomical Institutes of the Netherlands, v4 (1927), pp.21–38, "On the secular accelerations and the fluctuations of the moon, the sun, Mercury and Venus", which refers to "the 'astronomical time', given by the earth's rotation, and used in all practical astronomical computations", and states that it "differs from the 'uniform' or 'Newtonian' time".
↑ Rujuk khususnya F R Stephenson (1997), and Stephenson & Morrison (1995), buku dan kertas-kertas yang dipetik di bawah.
↑ (1) Dalam "The Physical Basis of the Leap Second", oleh D D McCarthy, C Hackman dan R A Nelson, dalam Astronomical Journal, jld. 136 (2008), ms. 1906–1908, adalah dinyatakan (ms 1908), bahawa "the SI second is equivalent to an older measure of the second of UT1, which was too small to start with and further, as the duration of the UT1 second increases, the discrepancy widens." :(2) Pada akhir 1950-an, piawaian sesium digunakan untuk menyukat jangka masa min semasa sesaat waktu suria min (UT2) (hasil: 9192631830 kitaran) dan juga sesaat waktu efemeris (ET) (hasil: 9192631770 +/-20 kitaran), rujuk "Time Scales", oleh L. Essen, dalam Metrologia, jld. 4 (1968), ms.161–165, di ms.162. Seperti yang sedia diketahui, angka 9192631770 terpilih untuk saat SI. L Essen dalam artikel 1968 yang sama (ms.162) menyatakan bahawa ini "seemed reasonable in view of the variations in UT2" (nampaknya munasabah memandangkan variasi dalam UT2).
