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Author image Sergey Krushinsky
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NAME

Astro::Montenbruck::NutEqu - Obliquity of the ecliptic & nutation.

SYNOPSIS

 # given mean geocentric coordinates $x0, $y0, $z0,
 # transform them to apparent coordinates $x1, $y1, $z1
 my $func = nutequ( $t );
 ($x1, $y1, $z1) = $func->($x0, $y0, $z0); # true coordinates

DESCRIPTION

Functions dealing with ecliptic obliquity.

SUBROUTINES

deltas( $t )

Calculates the effects of nutation on the ecliptic longitude and on the obliquity of the ecliptic with accuracy of about 1 arcsecond. Given time in Julian centuries since J2000, return delta-psi and delta-eps.

Arguments

  • $t — time in Julian centuries since J2000: (JD-2451545.0)/36525.0

Returns

($delta_psi, $delta_eps), in arc-degrees.

mean2true($t)

Returns function for transforming of mean to true coordinates.

Arguments

  • $t — time in Julian centuries since J2000: (JD-2451545.0)/36525.0

Returns

Function which takes mean ecliptic geocentric rectangular coordinates X, Y, Z of a planet and returns ecliptic rectangular coordinates, referred to the equinox of date.

obliquity( $t )

Given time in Julian centuries since J2000, return mean obliquity of the ecliptic, in arc-degrees.

AUTHOR

Sergey Krushinsky, <krushi at cpan.org>

COPYRIGHT AND LICENSE

Copyright (C) 2009-2021 by Sergey Krushinsky

This library is free software; you can redistribute it and/or modify it under the same terms as Perl itself.