Astro
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Astro/Coord.pm view on Meta::CPAN
coordinate system
Note: convert equitoral positions to/from 3-vectors using pol2r and r2pol.
@fk4 fk4 position to convert (as a 3-vector, turns)
@gal Galactic position (as a 3-vector, turns)
Returns undef if too few or two many arguments are passed.
Reference : Blaauw et al., 1960, MNRAS, 121, 123.
=cut
# Within 1e-7 arcsec of SLALIB slaEg50
sub fk4galr(@) {
# First check that we have 3 arguments
if (scalar @_ < 3) {
croak 'Not enough arguments for Astro::Coord::fk4galr at ';
} elsif (scalar @_ > 3) {
croak 'Too many arguments for Astro::Coord::fk4galr at ';
}
my ($i, $j, @temp, @gal);
my $w = 0.0;
Astro/Coord.pm view on Meta::CPAN
Notes: Converts equitoral positions to/from 3-vectors using pol2r and r2pol.
$BRA,$BDec fk4/B1950 position (turns)
$l, $b Galactic longitude and latitude
@gal Galactic position (as a 3-vector, turns)
@fk4 fk4 position (as a 3-vector, turns)
Reference : Blaauw et al., 1960, MNRAS, 121, 123.
=cut
# Within 1e-7 arcsec of SLALIB slaGe50
sub galfk4(@) {
my (@r, $rect);
if (@_==3) { # Rectangular coordinates passed
@r = @_;
$rect = 1;
} elsif (@_==2) { # Sperical coordinates
@r = pol2r($_[0],$_[1]); # Spherical to Cartesian
$rect = 0;
} elsif (@_>3) {
croak "Too many arguments for Astro::galfk4 at";
Astro/Coord.pm view on Meta::CPAN
$fk4[$i] = ($fk4[$i] + $eterm[$i])/$w;
}
if ($rect) {
return @fk4;
} else {
return r2pol(@fk4);
}
}
sub galfk4r(@) {galfk4(@_)};
#=item B<fk4fk5>
#
# ($JRA, $JDec) = fk4fk5($BRA, $BDec);
#
# Converts an FK4 (B1950) position to the equivalent FK5 (J2000) position.
# **LOW PRECISION**
# $BRA,$BDec fk4/B1950 position (turns)
# $JRA,$Dec fk5/J2000 position (turns)
#
Astro/Coord.pm view on Meta::CPAN
Converts an J2000 position date coordinate
$DRA,$DDec Date coordinate (turns)
$JRA,$Dec J2000 position (turns)
@date Date coordinate (as a 3-vector)
@J2000 J2000 position (as a 3-vector)
=cut
# Untested
sub J2000todate(@) {
my ($rect);
my (@J2000, @date); # Position vectors
my $mjd = pop @_;
if (@_==3) { # Rectangular coordinates passed
@J2000 = @_;
$rect = 1;
} elsif (@_==2) { # Sperical coordinates
@J2000 = pol2r($_[0],$_[1]); # Spherical to Cartesian
Astro/Coord.pm view on Meta::CPAN
The returned value is :
$haset - The hour angle (turns) at which a source at this
declination sets for an EWXY mounted antenna with the
given limits at the given latitude
NOTE: returns undef if %limits hash is missing any of the required keys
=cut
sub haset_ewxy($$\%) {
my ($declination, $latitude, $limitsref) = @_;
# Check that all the required keys are present
if ((!exists $limitsref->{XLOW}) || (!exists $limitsref->{XLOW_KEYHOLE}) ||
(!exists $limitsref->{XHIGH}) || (!exists $limitsref->{XHIGH_KEYHOLE}) ||
(!exists $limitsref->{YLOW}) || (!exists $limitsref->{YLOW_KEYHOLE}) ||
(!exists $limitsref->{YHIGH}) || (!exists $limitsref->{YHIGH_KEYHOLE})) {
carp 'Missing key in %limits';
return undef;
Astro/Coord.pm view on Meta::CPAN
\%limits - A reference to a hash holding the EWXY antenna limits
The following keys must be defined XLOW, XLOW_KEYHOLE,
XHIGH, XHIGH_KEYHOLE, YLOW, YLOW_KEYHOLE, YHIGH,
YHIGH_KEYHOLE (all values should be in turns)
The returned value is :
$tlos - The time left on-source (turns)
=cut
sub ewxy_tlos($$$\%) {
my ($hour_angle, $declination, $latitude, $limitsref) = @_;
my $haset = haset_ewxy($declination, $latitude, %$limitsref);
return(undef) if (!defined $haset);
$haset -= $hour_angle if (($haset > 0.0) && ($haset < 1.0));
$haset += 1.0 if ($haset < 0.0);
return $haset;
}
Astro/Coord.pm view on Meta::CPAN
The returned value is :
$haset - The hour angle (turns) at which a source at this
declination sets for an Az/El mounted antenna with the
given limits at the given latitude
NOTE: returns undef if the %limits hash is missing any of the required keys
=cut
sub haset_azel($$\%) {
my ($declination, $latitude, $limitsref) = @_;
# Check that all the required keys are present
if (!exists $limitsref->{ELLOW}) {
carp 'Missing key in %limits';
return undef ;
}
my $cos_haset = (cos($PI / 2.0 - $limitsref->{ELLOW} * 2.0 *
Astro/Coord.pm view on Meta::CPAN
$latitude - The latitude of the observatory (turns)
%limits - A reference to a hash holding the Az/El antenna limits
The following keys must be defined ELLOW (all values
should be in turns)
The returned value is :
$tlos - The time left on-source (turns)
=cut
sub azel_tlos($$$\%) {
my ($hour_angle, $declination, $latitude, $limitsref) = @_;
# Calculate the time left onsource
my $haset = haset_azel($declination, $latitude, %$limitsref);
if (!defined $haset) {return(undef)};
if (($haset > 0.0) && ($haset < 1.0)) { $haset -= $hour_angle; }
if ($haset < 0.0) { $haset += 1.0; }
return($haset);
}
Astro/Coord.pm view on Meta::CPAN
antenna there must be a key for ELLOW (all values should
be in turns).
The returned values are :
$ha_set - The hour angle at which the source sets (turns). The hour
angle at which the source rises is simply the negative of this
value.
=cut
sub antenna_rise($$$$) {
my ($declination, $latitude, $mount, $limitsref) = @_;
# Check that the mount type is either EWXY (0) or AZEL (1)
if (($mount != 0) && ($mount != 1)) {
carp 'mount must equal 0 or 1';
return undef;
}
if ($mount == 0) {
Astro/Coord.pm view on Meta::CPAN
}
my @b2g = ([-0.054875539726, 0.494109453312, -0.867666135858],
[-0.873437108010, -0.444829589425, -0.198076386122],
[-0.483834985808, 0.746982251810, 0.455983795705]);
#my @b2g = ([ -0.0548777621, +0.4941083214, -0.8676666398],
# [ -0.8734369591, -0.4448308610, -0.1980741871],
# [ -0.4838350026, +0.7469822433, +0.4559837919]);
sub j2gal($$) {
my ($ra,$dec) = @_;
my @r = pol2r($ra,$dec);
my @g = (0,0,0);
for (my $i=0; $i<3; $i++) {
for (my $j=0; $j<3; $j++) {
$g[$i]+= $b2g[$j][$i] * $r[$j];
}
}
return r2pol(@g);
}
Astro/Misc.pm view on Meta::CPAN
=item B<lum2spectral>
$spectral_type = lum2spectral($luminosity);
Calculate the spectral type of a ZAMS star from its luminosity
Based on Thompson 1984 ApJ 283 165 Table 1
$luminosity Star luminosity (normalised to Lsun)
=cut
sub lum2spectral($) {
my $lum = log10(shift);
my $n = scalar (@ThompsonData);
if ($lum < $ThompsonData[0][LUM]) {
return "<$ThompsonData[0][SPEC]";
} elsif ($lum > $ThompsonData[$n-1][LUM]) {
return ">$ThompsonData[$n-1][SPEC]";
};
$n = 1;
Astro/Time.pm view on Meta::CPAN
Winds back the day number by one, taking account of year wraps.
$dayno Day number of year
$year Year
$month Month
$day Day of month
=cut
# Verified
sub yesterday($$;$) {
my ($day, $month, $dayno, $year);
if (scalar(@_)==2) {
($dayno, $year) = @_;
return undef if (!daynoOK($dayno, $year));
} else {
($day, $month, $year) = @_;
return undef if (!monthOK($month));
return undef if (!dayOK($day, $month, $year));
Astro/Time.pm view on Meta::CPAN
Advances the day number by one, taking account of year wraps.
$dayno Day number of year
$year Year
$month Month
$day Day of month
=cut
# Verified
sub tomorrow($$;$) {
my ($day, $month, $dayno, $year);
if (scalar(@_)==2) {
($dayno, $year) = @_;
return undef if (!daynoOK($dayno, $year));
} else {
($day, $month, $year) = @_;
return undef if (!monthOK($month));
return undef if (!dayOK($day, $month, $year));
Astro/Time.pm view on Meta::CPAN
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
$ut UT day fraction
=cut
# VERIFIED
sub mjd2cal($) {
my $mjd = shift;
my $ut = fmod($mjd,1.0);
if ($ut<0.0) {
$ut += 1.0;
$mjd -= 1;
}
use integer; # Calculations require integer division and modulation
Astro/Time.pm view on Meta::CPAN
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
sub cal2mjd($$$;$) {
my($day, $month, $year, $ut) = @_;
$ut = 0.0 if (!defined $ut);
return undef if (!monthOK($month));
return undef if (!dayOK($day, $month, $year));
return undef if (!utOK($ut));
my ($m, $y);
if ($month <= 2) {
$m = int($month+9);
Astro/Time.pm view on Meta::CPAN
Converts a modified Julian day number into year and dayno (universal
time).
$mjd Modified Julian day (JD-2400000.5)
$year Year
$dayno Dayno of year
=cut
# NOT Verified
sub mjd2dayno($) {
my $mjd = shift;
my ($day, $month, $year, $ut) = mjd2cal($mjd);
return (cal2dayno($day,$month,$year), $year, $ut);
}
=item B<dayno2mjd>
$mjd = dayno2mjd($dayno, $year, $ut);
Converts a dayno and year to modified Julian day
$mjd Modified Julian day (JD-2400000.5)
$year Year
$dayno Dayno of year
=cut
# Not verified - wrapper to cal2mjd
sub dayno2mjd($$;$) {
my ($dayno, $year, $ut) = @_;
$ut = 0.0 if (!defined $ut);
return undef if (!daynoOK($dayno,$year));
return undef if (!utOK($ut));
my ($day, $month) = dayno2cal($dayno, $year);
return cal2mjd($day, $month, $year, $ut);
}
=item B<now2mjd>
$mjd = now2mjd()
=cut
# Not verified - just wrapper
sub now2mjd() {
my ($s, $m, $h, $day, $month, $year) = gmtime();
$month++;
$year += 1900;
return(cal2mjd($day, $month, $year, ((($s/60+$m)/60+$h)/24)));
}
=item B<jd2mjd>
$mjd = jd2mjd($jd);
Converts a Julian day to Modified Julian day
$jd Julian day
$mjd Modified Julian day
=cut
sub jd2mjd($) {
return (shift)-2400000.5;
}
=item B<mjd2jd>
$jd = mjd2jd($mjd);
Converts a Modified Julian day to Julian day
$mjd Modified Julian day
$jd Julian day
=cut
sub mjd2jd($) {
return (shift)+2400000.5;
}
=item B<mjd2time>
$str = mjd2time($mjd);
$str = mjd2time($mjd, $np);
Converts a Modified Julian day to a formatted string
$mjd Modified Julian day
$str Formatted time
$np Number of significant digits for fraction of a sec. Default 0
=cut
sub mjd2time($;$) {
my ($dayno, $year, $ut) = mjd2dayno(shift);
my $np = shift;
$np = 0 if (! defined $np);
return sprintf("$year %03d/%s", $dayno, turn2str($ut, 'H', $np));
}
=item B<mjd2vextime>
$str = mjd2vextime($mjd);
$str = mjd2vextime($mjd, $np);
Converts a Modified Julian day to a vex formatted string
$mjd Modified Julian day
$str Formatted time
$np Number of significant digits for fraction of a sec. Default 0
=cut
sub mjd2vextime($;$) {
my ($dayno, $year, $ut) = mjd2dayno(shift);
my $np = shift;
$np = 0 if (! defined $np);
return sprintf("%dy%03dd%s", $year, $dayno, turn2str($ut, 'H', $np, 'hms'));
}
=item B<mjd2epoch>
$time = mjd2epoch($mjd);
Converts a Modified Julian day to unix Epoch (seconds sinve 1 Jan 1970)
Rounded to the nearest second
$mjd Modified Julian day
$tie Seconds since 1 Jan 1970
=cut
sub mjd2epoch($) {
my $mjd = shift;
my $epoch = ($mjd - 40587)*24*60*60;
return int($epoch + $epoch/abs($epoch*2)); # Work even if epoch is negative
}
=item B<gst>
$gst = gst($mjd);
$gmst = gst($mjd, $dUT1);
$gtst = gst($mjd, $dUT1, $eqenx);
Astro/Time.pm view on Meta::CPAN
$mjd modified Julian day (JD-2400000.5)
$dUT1 difference between UTC and UT1 (UT1 = UTC + dUT1) (seconds)
$eqenx Equation of the equinoxes (not yet supported)
$gst Greenwich sidereal time (turns)
$gmst Greenwich mean sidereal time (turns)
$gtst Greenwich true sidereal time (turns)
=cut
# Verified
sub gst($;$$) {
my ($mjd, $dUT1, $eqenx) = @_;
$dUT1 = 0.0 if (! defined $dUT1);
if ($dUT1 > 0.5 || $dUT1 < -0.5) {
carp '$dUT1 out of range';
return undef;
}
if (defined $eqenx) {
croak '$eqenx is not supported yet';
}
Astro/Time.pm view on Meta::CPAN
$mjd Modified Julian day (JD-2400000.5)
$longitude Longitude for which the LST is required (turns)
$dUT1 Difference between UTC and UT1 (UT1 = UTC + dUT1)(seconds)
$eqenx Equation of the equinoxes (not yet supported)
$lst Local sidereal time (turns)
$lmst Local mean sidereal time (turns)
$ltst Local true sidereal time (turns)
=cut
sub mjd2lst($$;$$) {
my ($mjd, $longitude, $dUT1, $eqenx) = @_;
my $lst = gst($mjd, $dUT1, $eqenx);
return undef if (!defined $lst);
$lst += $longitude;
while ($lst>1.0) {
$lst-= 1;
}
while ($lst < 0.0) {
Astro/Time.pm view on Meta::CPAN
=item B<cal2lst>
$lst = cal2lst($day, $month, $year, $ut, $longitude);
$lmst = cal2lst($day, $month, $year, $ut, $longitude, $dUT1);
$ltst = cal2lst($day, $month, $year, $ut, $longitude, $dUT1, $eqenx);
Wrapper to mjd2lst using calendar date rather than mjd
=cut
sub cal2lst($$$$$;$$) {
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);
}
# Not verified
=item B<rise>
Astro/Time.pm view on Meta::CPAN
$lmst - The local mean sidereal time (turns)
$dayno - The UT day of year for which to do the conversion
$year - The year for which to do the conversion
$longitude - The longitude of the observatory (turns)
$dUT1 - Difference between UTC and UT1 (UT1 = UTC + dUT1)
(seconds)
$mjd The modified Julian day corresponding to $lmst on $dayno
=cut
sub lst2mjd($$$$;$) {
my ($lmst, $dayno, $year, $longitude, $dUT1) = @_;
$dUT1 = 0.0 if (!defined $dUT1);
my $SOLAR_TO_SIDEREAL = 1.002737909350795;
my $mjd = dayno2mjd($dayno, $year, $dUT1);
# Time in turns from passed lmst to lmst at the start of $dayno
my $delay = $lmst-mjd2lst($mjd, $longitude);
Astro/Time.pm view on Meta::CPAN
This routine returns the name of the given month (as a number 1..12),
where 1 is January. The default is a 3 character version of the month
('Jan', 'Feb', etc) in the second form the full month is returned
The required inputs are :
$month - The month in question with 1 == January.
=cut
sub month2str($;$) {
my ($mon, $long) = @_;
return undef if (!monthOK($mon));
if ($long) {
return $MonthStr[$mon-1];
} else {
return $MonthShortStr[$mon-1];
}
}
Astro/Time.pm view on Meta::CPAN
$weekdaystr = mjd2weekdaystr($mjd);
Returns the name of the weekday correspondig to the given MJD.
May not work for historical dates.
$mjd Modified Julian day (JD-2400000.5)
=cut
sub mjd2weekdaystr($;$) {
my ($mjd, $long) = @_;
my $dow = mjd2weekday($mjd);
if ($long) {
return $WeekStr[$dow];
} else {
return $WeekShortStr[$dow];
}
}
=item B<str2month>
Astro/Time.pm view on Meta::CPAN
Given the name of a month (in English), this routine returns the
an integer between 1 and 12, where 1 is January. Full month names of
3 character abbreviations are acceptable. Minumum matching (e.g. "Marc")
is not supported.
The required inputs are :
$month - Name of the month ('Jan', 'January', 'Feb', 'February' etc)
=cut
sub str2month($) {
my $month = uc(shift);
for (my $i=0; $i<12; $i++) {
if ($month eq uc($MonthStr[$i]) || $month eq uc($MonthShortStr[$i])) {
return $i+1;
}
}
return undef;
}
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