Astro

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Astro/Time.pm  view on Meta::CPAN

    $dayno = cal2dayno($day, $month, $year);
    print "It's a leap year!\n" if (leap($year));
    $lmst = mjd2lst($mjd, $longitude, $dUT1);
    $turns = str2turn($string, 'H');
    $str = turn2str($turn, 'D', $sig);

=head1 DESCRIPTION

Astro::Time contains an assorted set Perl routines for time based
conversions, such as conversion between calendar dates and Modified
Julian day and conversion of UT to local sidereal time. Include are
routines for conversion between numerical and string representation of
angles.

=head1 AUTHOR

Chris Phillips  Chris.Phillips@csiro.au

=head1 FUNCTIONS

Astro/Time.pm  view on Meta::CPAN

  } else {
    ($day, $month) = dayno2cal($dayno, $year);
    return($day, $month, $year);
  }
}

=item B<mjd2cal>

  ($day, $month, $year, $ut) = mjd2cal($mjd);

 Converts a modified Julian day number into calendar date (universal 
 time). (based on the slalib routine sla_djcl).
    $mjd     Modified Julian day (JD-2400000.5)
    $day     Day of the month.
    $month   Month of the year.
    $year    Year
    $ut      UT day fraction

=cut

# VERIFIED

Astro/Time.pm  view on Meta::CPAN

  my $month =(($temp2/306+2)%12)+1;
  my $day = ($temp2%306)/10+1;

  return($day, $month, $year, $ut);
}

=item B<cal2mjd>

  $mjd = cal2mjd($day, $month, $year, $ut);

 Converts a calendar date (universal time) into modified Julian day 
 number.
    $day     Day of the month.
    $month   Month of the year.
    $year    Year
    $ut      UT dayfraction
    $mjd     Modified Julian day (JD-2400000.5)

=cut

# Verified

Astro/Time.pm  view on Meta::CPAN

  }
  return $lst;
}

=item B<cal2lst>

  $lst = cal2lst($day, $month, $year, $ut, $longitude);
  $lmst = cal2lst($day, $month, $year, $ut, $longitude, $dUT1);
  $ltst = cal2lst($day, $month, $year, $ut, $longitude, $dUT1, $eqenx);

 Wrapper to mjd2lst using calendar date rather than mjd

=cut

sub cal2lst($$$$$;$$) {
  my ($day, $month, $year, $ut, $longitude, $dUT1, $eqenx) = @_;
  my $mjd = cal2mjd($day, $month, $year, $ut);
  return undef if (!defined $mjd);

  return mjd2lst($mjd, $longitude, $dUT1, $eqenx);
}

=item B<dayno2lst>

  $lst = dayno2lst($dayno, $year, $ut, $longitude);
  $lmst = dayno2lst($dayno, $year, $ut, $longitude, $dUT1);
  $ltst = dayno2lst($dayno, $year, $ut, $longitude, $dUT1, $eqenx);

 Wrapper to mjd2lst using calendar date rather than mjd

=cut

sub dayno2lst($$$$;$$) {
  my ($dayno, $year, $ut, $longitude, $dUT1, $eqenx) = @_;
  my $mjd = dayno2mjd($dayno, $year, $ut);
  return undef if (!defined $mjd);

  return mjd2lst($mjd, $longitude,  $dUT1, $eqenx);
}

README  view on Meta::CPAN

Astro::	- Assorted astronomical routines

Astro::Time, Astro::Coord and Astro::Misc provide a collection of useful
astronomical routines written entirely in Perl (so no hassling about
installing external libraries is required).

The routines provided include various time conversions (dayno to day/month,
local sidereal time, calendar to Modified Julian day) and coordinate
transformations (J2000 to B1950, B1950 to Galactic, Az,El to Ha,Dec),
string parsing (12:00:00 -> 0.5) as well as a number of astronomical tools
(eg observed Galactic velocity to kinematic distance).

These routines should be used at your own risk! Most should give
reasonable accurate results, but spot checks against your favorite
program are recommenced. The B1950/J2000/Galactic coordinate routines
are based on SLALIB routines and agree very closely.

Please let me know of any bugs you find or if you have other routines you