Kstars

ksearthshadow.h
1/*
2 SPDX-FileCopyrightText: 2018 Valentin Boettcher <valentin@boettcher.cf (do not hesitate to contact)>
3 matrix : @hiro98@tchncs.de
4
5 SPDX-License-Identifier: GPL-2.0-or-later
6*/
7
8#pragma once
9
10#include "ksplanetbase.h"
11
12class KSSun;
13class KSMoon;
14class KSPlanet;
15
16/**
17 * @class KSEarthShadow
18 * @short A class that manages the calculation of the
19 * earths shadow (in moon distance) as a 'virtual' skyobject.
20 * KSMoon is responsible for coordinating this object. While a
21 * rather unusual measure, this method ensures that unnecessary
22 * calculations are avoided.
23 *
24 * @author Valentin Boettcher
25 * @version 1.0
26 */
27class KSEarthShadow : public KSPlanetBase
28{
29 public:
30 /**
31 * @param moon - an instance of KSMoon
32 * @param sun - an instance of KSSun
33 * @param earth - an instance of KSPlanet
34 * @note The three parameters must be supplied to avoid initialization order
35 * problems. This class may be generalized to any three bodies if it becomes
36 * necessary in the future.
37 * This class is relatively cheap, so it's save to create new instances instead
38 * of reusing an existing one.
39 */
40 KSEarthShadow(const KSMoon *moon, const KSSun *sun, const KSPlanet * earth);
41
42 /**
43 * @brief The ECLIPSE_TYPE enum describes the quality of an eclipse.
44 */
45 enum ECLIPSE_TYPE
46 {
47 PARTIAL, FULL_PENUMBRA, FULL_UMBRA, NONE
48 };
49
50 /**
51 * @short The earths shadow on the moon appears only at new moon
52 * so calculating it on other occasions is rather pointless.
53 * @return whether to update the shadow or not
54 */
55 bool shouldUpdate();
56
57
58 /**
59 * @brief isInEclipse - a slim version of getEclipseType()
60 * @return Whether the earth shadow eclipses the moon.
61 */
62 bool isInEclipse();
63
64 /**
65 * @brief eclipse
66 * @return The eclipse type. @see KSEarthShadow::ECLIPSE_TYPE
67 */
68 ECLIPSE_TYPE getEclipseType();
69
70 bool findGeocentricPosition(const KSNumbers *, const KSPlanetBase * Earth = nullptr) override;
71
72 /**
73 * @short Update the Coordinates of the shadow.
74 * In truth it finds the sun and calls KSEarthShadow::updateCoords(const KSSun *)
75 */
76 void updateCoords(const KSNumbers *num, bool includePlanets = true, const CachingDms *lat = nullptr,
77 const CachingDms *LST = nullptr, bool forceRecompute = false) override;
78
79 /**
80 * @short Update the RA/DEC of the shadow.
81 */
82 void updateCoords();
83
84 /**
85 * @short Updates umbra and penumbra radius from the positions of the three bodies.
86 */
87 void calculateShadowRadius();
88
89 /**
90 * @return The angular radius of the umbra.
91 */
92 double getUmbraAngSize() const
93 {
94 return m_umbra_ang;
95 }
96
97 /**
98 * @return The angular radius of the penumbra.
99 */
100 double getPenumbraAngSize() const
101 {
102 return m_penumbra_ang;
103 }
104
105 /**
106 * @brief angSize
107 * @return the angular size (penumbra) in arc minutes
108 */
109 double findAngularSize() final override
110 {
111 calculateShadowRadius();
112 return m_penumbra_ang;
113 }
114
115 // Some Compatibility Nonsense
116 void findMagnitude(const KSNumbers *) override {} // Empty
117 bool loadData() override
118 {
119 return true;
120 }
121 void findPhase() override {}
122
123 private:
124 double m_umbra_ang { 0 }; // Radius!
125 double m_penumbra_ang { 0 }; // Radius!
126
127 const KSSun* m_sun { nullptr };
128 const KSMoon* m_moon { nullptr };
129 const KSPlanet* m_earth { nullptr };
130
131 void findSun();
132 void findMoon();
133 void findEarth();
134};
CachingDms
a dms subclass that caches its sine and cosine values every time the angle is changed.
Definition cachingdms.h:19
KSEarthShadow
A class that manages the calculation of the earths shadow (in moon distance) as a 'virtual' skyobject...
Definition ksearthshadow.h:28
KSEarthShadow::findMagnitude
void findMagnitude(const KSNumbers *) override
Computes the visual magnitude for the major planets.
Definition ksearthshadow.h:116
KSEarthShadow::updateCoords
void updateCoords()
Update the RA/DEC of the shadow.
Definition ksearthshadow.cpp:58
KSEarthShadow::findPhase
void findPhase() override
Determine the phase of the planet.
Definition ksearthshadow.h:121
KSEarthShadow::findGeocentricPosition
bool findGeocentricPosition(const KSNumbers *, const KSPlanetBase *Earth=nullptr) override
find the object's current geocentric equatorial coordinates (RA and Dec) This function is pure virtua...
Definition ksearthshadow.cpp:45
KSEarthShadow::shouldUpdate
bool shouldUpdate()
The earths shadow on the moon appears only at new moon so calculating it on other occasions is rather...
Definition ksearthshadow.cpp:15
KSEarthShadow::getPenumbraAngSize
double getPenumbraAngSize() const
Definition ksearthshadow.h:100
KSEarthShadow::getEclipseType
ECLIPSE_TYPE getEclipseType()
eclipse
Definition ksearthshadow.cpp:26
KSEarthShadow::KSEarthShadow
KSEarthShadow(const KSMoon *moon, const KSSun *sun, const KSPlanet *earth)
Definition ksearthshadow.cpp:10
KSEarthShadow::isInEclipse
bool isInEclipse()
isInEclipse - a slim version of getEclipseType()
Definition ksearthshadow.cpp:20
KSEarthShadow::findAngularSize
double findAngularSize() final override
angSize
Definition ksearthshadow.h:109
KSEarthShadow::ECLIPSE_TYPE
ECLIPSE_TYPE
The ECLIPSE_TYPE enum describes the quality of an eclipse.
Definition ksearthshadow.h:46
KSEarthShadow::getUmbraAngSize
double getUmbraAngSize() const
Definition ksearthshadow.h:92
KSEarthShadow::calculateShadowRadius
void calculateShadowRadius()
Updates umbra and penumbra radius from the positions of the three bodies.
Definition ksearthshadow.cpp:71
KSMoon
Provides necessary information about the Moon.
Definition ksmoon.h:26
KSNumbers
There are several time-dependent values used in position calculations, that are not specific to an ob...
Definition ksnumbers.h:43
KSPlanetBase
A subclass of TrailObject that provides additional information needed for most solar system objects.
Definition ksplanetbase.h:50
KSPlanet
A subclass of KSPlanetBase for seven of the major planets in the solar system (Earth and Pluto have t...
Definition ksplanet.h:33
KSSun
Child class of KSPlanetBase; encapsulates information about the Sun.
Definition kssun.h:24
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