Delta T : Polynomial Approximation of Time Period 1620–2013

Abstract EN

The difference between the Uniform Dynamical Time and Universal Time is referred to as ΔT (delta T).

Delta T is used in numerous astronomical calculations, that is, eclipses,and length of day.

It is additionally required to reduce quantified positions of minor planets to a uniform timescale for the purpose of orbital determination.

Since Universal Time is established on the basis of the variable rotation of planet Earth, the quantity ΔT mirrors the unevenness of that rotation, and so it changes slowly, but rather irregularly, as time passes.

We have worked on empirical formulae for estimating ΔT and have discovered a set of polynomials of the 4th order with nine intervals which is accurate within the range of ±0.6 seconds for the duration of years 1620–2013.