1,516 research outputs found

    Numerical Evaluation Of the Oscillatory Integral over exp(i*pi*x)*x^(1/x) between 1 and infinity

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    Real and imaginary part of the limit 2N->infinity of the integral int_{x=1..2N} exp(i*pi*x)*x^(1/x) dx are evaluated to 20 digits with brute force methods after multiple partial integration, or combining a standard Simpson integration over the first halve wave with series acceleration techniques for the alternating series co-phased to each of its points. The integrand is of the logarithmic kind; its branch cut limits the performance of integration techniques that rely on smooth higher order derivatives.Comment: Section 2.5 (approach of modified integration path in the complex plane) adde

    A Java Program Generating Barycentric Observer Velocities from JPL Ephemerides

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    This works presents a program which computes velocities of an Earth-bound observatory in the reference frame of the barycenter of the solar system. It feeds from ephemerides files of the Jet Propulsion Laboratory to extract the velocity of the geocenter, optionally with corrections from Earth rotation data of the International Earth Rotation Service, takes a datum (time and geodetic location) of the observer as parameters, and processes these data with the program library of the working group `Standards of Fundamental Astronomy' of the International Astronomical Union. The prospective application of the computed velocities is to subtract their projection onto a pointing direction from observed velocities in a step of data reduction of astronomic radial velocities.Comment: Version 5: includes scanner for DE440/DE441 and generator for MPC equatorial coordinate
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