/**
* Performs a [IRCS -> observed] coordinate transformation for the parameters
* of this instance
* @param string $type Coordintate type, 'e' for equat 'h' for horiz
* @return static|Horiz
*/
protected function ICRStoObserved($type = 'e', Pressure $pressure = null, Temperature $temp = null, $humidity = null)
{
// Instance initial properties
$rc = $this->ra->toAngle()->rad;
$dc = $this->dec->rad;
$date1 = $this->epoch->toDate()->toTDB()->toJD();
$pr = 0;
$pd = 0;
$rv = 0;
$px = $this->dist->au > 0 ? 8.794 / 3600 / $this->dist->au : 0;
$utc1 = $this->epoch->toDate()->toUTC()->toJD();
$dut1 = IERS::jd($utc1)->dut1();
$elong = $this->topo ? $this->topo->lon->rad : 0;
$phi = $this->topo ? $this->topo->lat->rad : 0;
$hm = 0;
//$this->obsrv->height->m;
$xp = IERS::jd($utc1)->x() / 3600 * pi() / 180;
$yp = IERS::jd($utc1)->y() / 3600 * pi() / 180;
$phpa = $pressure ? $pressure->mbar : 0;
$tc = $temp ? $temp->c : 0;
$rh = $humidity ? $humidity : 0;
$wl = 0.55;
// ICRS -> CIRS (geocentric observer)
IAU::Atci13($rc, $dc, $pr, $pd, $px, $rv, $date1, 0, $ri, $di, $eo);
// CIRS -> ICRS (astrometric)
//IAU::Atic13($ri, $di, $date1, 0, $rca, $dca, $eo);
// ICRS (astrometric) -> CIRS (geocentric observer)
//IAU::Atci13($rca, $dca, $pr, $pd, $px, $rv, $date1, 0, $ri, $di, $eo);
// Apparent place ?
//$ri = $ri - $eo;
//$di = $di;
//
// CIRS -> topocentric
IAU::Atio13($ri, $di, $utc1, 0, $dut1, $elong, $phi, $hm, $xp, $yp, $phpa, $tc, $rh, $wl, $aob, $zob, $hob, $dob, $rob);
if ($type == 'e') {
// Copy this instance, and override the apparent RA and Decl
$topocentric = $this->copy();
$topocentric->ra = Angle::rad($rob)->toTime();
$topocentric->dec = Angle::rad($dob);
$topocentric->apparent = true;
// Return apparent coordinates
return $topocentric;
} else {
// Prepare new horizontal instance
$horiz = new Horiz(Angle::rad(deg2rad(90) - $zob), Angle::rad($aob), $this->dist);
return $horiz;
}
}
/**
* Converts this instance to Universal Time (UT1)
* @return static
*/
public function toUT1()
{
if ($this->timescale == TimeScale::UT1()) {
return $this;
}
$this->toUTC();
$utc1 = $this->jd;
$utc2 = $this->dayFrac;
$dut1 = IERS::jd($utc1 + $utc2)->dut1();
IAU::Utcut1($utc1, $utc2, $dut1, $ut11, $ut12);
$this->jd = $ut11;
$this->dayFrac = $ut12;
$this->timescale = TimeScale::UT1();
return $this;
}