skyobject.cpp

/*
    SPDX-FileCopyrightText: 2001 Jason Harris <jharris@30doradus.org>
 
    SPDX-License-Identifier: GPL-2.0-or-later
*/
 
#include "skyobject.h"
 
#include "geolocation.h"
#include "ksnumbers.h"
#include "kspaths.h"
#ifdef KSTARS_LITE
#include "skymaplite.h"
#else
#include "kspopupmenu.h"
#include "skymap.h"
#endif
#include "kstarsdata.h"
#include "Options.h"
#include "starobject.h"
#include "skycomponents/skylabeler.h"
 
 
const SkyObject::UID SkyObject::invalidUID   = ~0;
const SkyObject::UID SkyObject::UID_STAR     = 0;
const SkyObject::UID SkyObject::UID_GALAXY   = 1;
const SkyObject::UID SkyObject::UID_DEEPSKY  = 2;
const SkyObject::UID SkyObject::UID_SOLARSYS = 3;
 
SkyObject::SkyObject(int t, dms r, dms d, float m, const QString &n, const QString &n2, const QString &lname)
    : SkyPoint(r, d)
{
    setType(t);
    sortMagnitude = m;
    setName(n);
    setName2(n2);
    setLongName(lname);
}
 
SkyObject::SkyObject(int t, double r, double d, float m, const QString &n, const QString &n2, const QString &lname)
    : SkyPoint(r, d)
{
    setType(t);
    sortMagnitude = m;
    setName(n);
    setName2(n2);
    setLongName(lname);
}
 
SkyObject *SkyObject::clone() const
{
    Q_ASSERT(typeid(this) == typeid(static_cast<const SkyObject *>(this))); // Ensure we are not slicing a derived class
    return new SkyObject(*this);
}
 
void SkyObject::showPopupMenu(KSPopupMenu *pmenu, const QPoint &pos)
{
#if defined(KSTARS_LITE)
    Q_UNUSED(pos)
    Q_UNUSED(pmenu);
#else
    initPopupMenu(pmenu);
    pmenu->popup(pos);
#endif
}
 
void SkyObject::initPopupMenu(KSPopupMenu *pmenu)
{
#ifdef KSTARS_LITE
    Q_UNUSED(pmenu)
#else
    pmenu->createEmptyMenu(this);
#endif
}
 
void SkyObject::setLongName(const QString &longname)
{
    if (longname.isEmpty())
    {
        if (hasName())
            LongName = name();
        else if (hasName2())
            LongName = name2();
        else
            LongName.clear();
    }
    else
    {
        LongName = longname;
    }
}
 
QTime SkyObject::riseSetTime(const KStarsDateTime &dt, const GeoLocation *geo, bool rst, bool exact) const
{
    // If this object does not rise or set, return an invalid time
    SkyPoint p = recomputeCoords(dt, geo);
    if (p.checkCircumpolar(geo->lat()))
        return QTime();
 
    //First of all, if the object is below the horizon at date/time dt, adjust the time
    //to bring it above the horizon
    KStarsDateTime dt2 = dt;
    dms lst(geo->GSTtoLST(dt.gst()));
    p.EquatorialToHorizontal(&lst, geo->lat());
    if (p.alt().Degrees() < 0.0)
    {
        if (p.az().Degrees() < 180.0) //object has not risen yet
        {
            dt2 = dt.addSecs(12. * 3600.); // Move forward 12 hours, to a time when it has already risen
        }
        else //object has already set
        {
            dt2 = dt.addSecs(-12. * 3600.); // Move backward 12 hours, to a time when it has not yet set
        }
    }
    // The addition / subtraction of 12 hours ensures that we always
    // compute the _closest_ rise time and the _closest_ set time to
    // the current time.
 
    QTime rstUt = riseSetTimeUT(dt2, geo, rst, exact);
    if (!rstUt.isValid())
        return QTime();
 
    return geo->UTtoLT(KStarsDateTime(dt2.date(), rstUt)).time();
}
 
QTime SkyObject::riseSetTimeUT(const KStarsDateTime &dt, const GeoLocation *geo, bool riseT, bool exact) const
{
    // First trial to calculate UT
    QTime UT = auxRiseSetTimeUT(dt, geo, &ra(), &dec(), riseT);
 
    // We iterate once more using the calculated UT to compute again
    // the ra and dec for that time and hence the rise/set time.
    // Also, adjust the date by +/- 1 day, if necessary
 
    // By adding this +/- 1 day, we are double-checking that the
    // reported rise-time is the _already_ (last) risen time, and that
    // the reported set-time is the _future_ (next) set time
    //
    // However, issues with this are taken care of in
    // SkyObject::riseSetTime()
 
    KStarsDateTime dt0 = dt;
    dt0.setTime(UT);
    if (riseT && dt0 > dt)
    {
        dt0 = dt0.addDays(-1);
    }
    else if (!riseT && dt0 < dt)
    {
        dt0 = dt0.addDays(1);
    }
 
    SkyPoint sp = recomputeCoords(dt0, geo);
    UT          = auxRiseSetTimeUT(dt0, geo, &sp.ra(), &sp.dec(), riseT);
 
    if (exact)
    {
        // We iterate a second time (For the Moon the second iteration changes
        // aprox. 1.5 arcmin the coordinates).
        dt0.setTime(UT);
        sp = recomputeCoords(dt0, geo);
        UT = auxRiseSetTimeUT(dt0, geo, &sp.ra(), &sp.dec(), riseT);
    }
 
    return UT;
}
 
QTime SkyObject::auxRiseSetTimeUT(const KStarsDateTime &dt, const GeoLocation *geo, const dms *righta, const dms *decl,
                                  bool riseT) const
{
    dms LST = auxRiseSetTimeLST(geo->lat(), righta, decl, riseT);
    return dt.GSTtoUT(geo->LSTtoGST(LST));
}
 
dms SkyObject::auxRiseSetTimeLST(const dms *gLat, const dms *righta, const dms *decl, bool riseT) const
{
    dms h0   = elevationCorrection();
    double H = approxHourAngle(&h0, gLat, decl);
    dms LST;
 
    if (riseT)
        LST.setH(24.0 + righta->Hours() - H / 15.0);
    else
        LST.setH(righta->Hours() + H / 15.0);
 
    return LST.reduce();
}
 
dms SkyObject::riseSetTimeAz(const KStarsDateTime &dt, const GeoLocation *geo, bool riseT) const
{
    dms Azimuth;
    double AltRad, AzRad;
    double sindec, cosdec, sinlat, coslat, sinHA, cosHA;
    double sinAlt, cosAlt;
 
    QTime UT           = riseSetTimeUT(dt, geo, riseT);
    KStarsDateTime dt0 = dt;
    dt0.setTime(UT);
    SkyPoint sp = recomputeCoords(dt0, geo);
 
    dms LST       = auxRiseSetTimeLST(geo->lat(), &sp.ra0(), &sp.dec0(), riseT);
    dms HourAngle = dms(LST.Degrees() - sp.ra0().Degrees());
 
    geo->lat()->SinCos(sinlat, coslat);
    dec().SinCos(sindec, cosdec);
    HourAngle.SinCos(sinHA, cosHA);
 
    sinAlt = sindec * sinlat + cosdec * coslat * cosHA;
    AltRad = asin(sinAlt);
    cosAlt = cos(AltRad);
 
    AzRad = acos((sindec - sinlat * sinAlt) / (coslat * cosAlt));
    if (sinHA > 0.0)
        AzRad = 2.0 * dms::PI - AzRad; // resolve acos() ambiguity
    Azimuth.setRadians(AzRad);
 
    return Azimuth;
}
 
QTime SkyObject::transitTimeUT(const KStarsDateTime &dt, const GeoLocation *geo) const
{
    dms LST = geo->GSTtoLST(dt.gst());
 
    //dSec is the number of seconds until the object transits.
    dms HourAngle = dms(LST.Degrees() - ra().Degrees());
    int dSec      = static_cast<int>(-3600. * HourAngle.Degrees() / 15.0);
 
    //dt0 is the first guess at the transit time.
    KStarsDateTime dt0 = dt.addSecs(dSec);
    //recompute object's position at UT0 and then find transit time of this refined position
    SkyPoint sp = recomputeCoords(dt0, geo);
    HourAngle = dms(LST.Degrees() - sp.ra().Degrees());
    dSec      = static_cast<int>(-3600. * HourAngle.Degrees() / 15.0);
 
    return dt.addSecs(dSec).time();
}
 
QTime SkyObject::transitTime(const KStarsDateTime &dt, const GeoLocation *geo) const
{
    return geo->UTtoLT(KStarsDateTime(dt.date(), transitTimeUT(dt, geo))).time();
}
 
dms SkyObject::transitAltitude(const KStarsDateTime &dt, const GeoLocation *geo) const
{
    KStarsDateTime dt0 = dt;
    dt0.setTime(transitTimeUT(dt, geo));
    SkyPoint sp = recomputeCoords(dt0, geo);
 
    double delta = 90 - geo->lat()->Degrees() + sp.dec().Degrees();
    if (delta > 90)
        delta = 180 - delta;
    return dms(delta);
}
 
double SkyObject::approxHourAngle(const dms *h0, const dms *gLat, const dms *dec) const
{
    double sh0 = sin(h0->radians());
    double r   = (sh0 - sin(gLat->radians()) * sin(dec->radians())) / (cos(gLat->radians()) * cos(dec->radians()));
 
    double H = acos(r) / dms::DegToRad;
 
    return H;
}
 
dms SkyObject::elevationCorrection(void) const
{
    /* The atmospheric refraction at the horizon shifts altitude by
     * - 34 arcmin = 0.5667 degrees. This value changes if the observer
     * is above the horizon, or if the weather conditions change much.
     *
     * For the sun we have to add half the angular sie of the body, since
     * the sunset is the time the upper limb of the sun disappears below
     * the horizon, and dawn, when the upper part of the limb appears
     * over the horizon. The angular size of the sun = angular size of the
     * moon = 31' 59''.
     *
     * So for the sun the correction is = -34 - 16 = 50 arcmin = -0.8333
     *
     * This same correction should be applied to the moon however parallax
     * is important here. Meeus states that the correction should be
     * 0.7275 P - 34 arcmin, where P is the moon's horizontal parallax.
     * He proposes a mean value of 0.125 degrees if no great accuracy
     * is needed.
     */
 
    if (name() == i18n("Sun") || name() == i18n("Moon") || name() == i18n("Earth Shadow"))
        return dms(-0.8333);
    //  else if ( name() == "Moon" )
    //      return dms(0.125);
    else // All sources point-like.
        return dms(-0.5667);
}
 
SkyPoint SkyObject::recomputeCoords(const KStarsDateTime &dt, const GeoLocation *geo) const
{
    // Create a clone
    SkyObject *c = this->clone();
 
    // compute coords of the copy for new time jd
    KSNumbers num(dt.djd());
 
    // Note: isSolarSystem() below should give the same result on this
    // and c. The only very minor reason to prefer this is so that we
    // have an additional layer of warnings about subclasses of
    // KSPlanetBase that do not implement SkyObject::clone() due to
    // the passing of lat and LST
 
    if (isSolarSystem() && geo)
    {
        CachingDms LST = geo->GSTtoLST(dt.gst());
        c->updateCoords(&num, true, geo->lat(), &LST);
    }
    else
    {
        c->updateCoords(&num);
    }
 
    // Transfer the coordinates into a SkyPoint
    SkyPoint p = *c;
 
    // Delete the clone
    delete c;
 
    // Return the SkyPoint
    return p;
}
 
SkyPoint SkyObject::recomputeHorizontalCoords(const KStarsDateTime &dt, const GeoLocation *geo) const
{
    Q_ASSERT(geo);
    SkyPoint ret   = recomputeCoords(dt, geo);
    CachingDms LST = geo->GSTtoLST(dt.gst());
    ret.EquatorialToHorizontal(&LST, geo->lat());
    return ret;
}
 
QString SkyObject::typeName(int t)
{
    switch (t)
    {
        case STAR:
            return i18n("Star");
        case CATALOG_STAR:
            return i18n("Catalog Star");
        case PLANET:
            return i18n("Planet");
        case OPEN_CLUSTER:
            return i18n("Open Cluster");
        case GLOBULAR_CLUSTER:
            return i18n("Globular Cluster");
        case GASEOUS_NEBULA:
            return i18n("Gaseous Nebula");
        case PLANETARY_NEBULA:
            return i18n("Planetary Nebula");
        case SUPERNOVA_REMNANT:
            return i18n("Supernova Remnant");
        case GALAXY:
            return i18n("Galaxy");
        case COMET:
            return i18n("Comet");
        case ASTEROID:
            return i18n("Asteroid");
        case CONSTELLATION:
            return i18n("Constellation");
        case MOON:
            return i18n("Moon");
        case GALAXY_CLUSTER:
            return i18n("Galaxy Cluster");
        case SATELLITE:
            return i18n("Satellite");
        case SUPERNOVA:
            return i18n("Supernova");
        case RADIO_SOURCE:
            return i18n("Radio Source");
        case ASTERISM:
            return i18n("Asterism");
        case DARK_NEBULA:
            return i18n("Dark Nebula");
        case QUASAR:
            return i18n("Quasar");
        case MULT_STAR:
            return i18n("Multiple Star");
        default:
            return i18n("Unknown Type");
    }
}
 
QString SkyObject::typeName() const
{
    return typeName(Type);
}
 
QString SkyObject::messageFromTitle(const QString &imageTitle) const
{
    QString message = imageTitle;
 
    //HST Image
    if (imageTitle == i18n("Show HST Image") || imageTitle.contains("HST"))
    {
        message = i18n("%1: Hubble Space Telescope, operated by STScI for NASA [public domain]", longname());
 
        //Spitzer Image
    }
    else if (imageTitle.contains(i18n("Show Spitzer Image")))
    {
        message = i18n("%1: Spitzer Space Telescope, courtesy NASA/JPL-Caltech [public domain]", longname());
 
        //SEDS Image
    }
    else if (imageTitle == i18n("Show SEDS Image"))
    {
        message = i18n("%1: SEDS, http://www.seds.org [free for non-commercial use]", longname());
 
        //Kitt Peak AOP Image
    }
    else if (imageTitle == i18n("Show KPNO AOP Image"))
    {
        message = i18n("%1: Advanced Observing Program at Kitt Peak National Observatory [free for non-commercial use; "
                       "no physical reproductions]",
                       longname());
 
        //NOAO Image
    }
    else if (imageTitle.contains(i18n("Show NOAO Image")))
    {
        message =
            i18n("%1: National Optical Astronomy Observatories and AURA [free for non-commercial use]", longname());
 
        //VLT Image
    }
    else if (imageTitle.contains("VLT"))
    {
        message = i18n("%1: Very Large Telescope, operated by the European Southern Observatory [free for "
                       "non-commercial use; no reproductions]",
                       longname());
 
        //All others
    }
    else if (imageTitle.startsWith(i18n("Show")))
    {
        message = imageTitle.mid(imageTitle.indexOf(" ") + 1); //eat first word, "Show"
        message = longname() + ": " + message;
    }
 
    return message;
}
 
QString SkyObject::labelString() const
{
    return translatedName();
}
 
double SkyObject::labelOffset() const
{
    return SkyLabeler::ZoomOffset();
}
 
SkyObject::UID SkyObject::getUID() const
{
    return invalidUID;
}