350 lines
14 KiB
JavaScript
350 lines
14 KiB
JavaScript
/* AstroTools – Echter Sternenhimmel mit Sternbildern
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Sternwarte Sonneberg · 50°22′N · 11°11′O
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──────────────────────────────────────────────── */
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(function () {
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/* ── Standort ───────────────────────────────── */
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const LAT = 50.377; // Grad Nord
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const LON = 11.189; // Grad Ost
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/* ── Sternkatalog ───────────────────────────────
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[RA (Stunden), Dek (Grad), Magnitude]
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─────────────────────────────────────────────── */
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const CAT = [
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// Orion
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[ 5.919, 7.407, 0.42], // 0 Betelgeuse
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[ 5.242, -8.202, 0.12], // 1 Rigel
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[ 5.419, 6.350, 1.64], // 2 Bellatrix
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[ 5.533, -0.299, 2.23], // 3 Mintaka
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[ 5.603, -1.202, 1.69], // 4 Alnilam
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[ 5.679, -1.943, 1.77], // 5 Alnitak
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[ 5.796, -9.670, 2.06], // 6 Saiph
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// Ursa Major (Großer Wagen)
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[11.062, 61.751, 1.79], // 7 Dubhe
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[11.031, 56.383, 2.37], // 8 Merak
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[11.897, 53.695, 2.44], // 9 Phecda
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[12.257, 57.033, 3.31], // 10 Megrez
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[12.900, 55.960, 1.76], // 11 Alioth
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[13.399, 54.925, 2.23], // 12 Mizar
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[13.792, 49.313, 1.85], // 13 Alkaid
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// Ursa Minor (Kleiner Wagen)
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[ 2.530, 89.264, 1.97], // 14 Polaris
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[14.845, 74.156, 2.08], // 15 Kochab
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[15.345, 71.834, 3.05], // 16 Pherkad
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// Cassiopeia (W)
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[ 0.153, 59.150, 2.27], // 17 Caph
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[ 0.675, 56.537, 2.24], // 18 Schedar
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[ 0.945, 60.717, 2.15], // 19 Cih (γ Cas)
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[ 1.430, 60.235, 2.68], // 20 Ruchbah
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[ 1.907, 63.670, 3.38], // 21 Segin
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// Gemini (Zwillinge)
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[ 7.755, 28.026, 1.14], // 22 Pollux
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[ 7.577, 31.888, 1.57], // 23 Castor
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[ 6.629, 16.399, 1.93], // 24 Alhena
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[ 7.335, 21.982, 3.53], // 25 Wasat
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[ 6.882, 25.131, 2.98], // 26 Mebsuda
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[ 6.379, 22.514, 3.28], // 27 Propus
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// Taurus (Stier)
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[ 4.599, 16.509, 0.85], // 28 Aldebaran
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[ 5.438, 28.608, 1.65], // 29 Elnath
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[ 3.791, 24.105, 2.85], // 30 Alcyone (Pleiaden)
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[ 4.477, 19.181, 3.53], // 31 Ain
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// Auriga (Fuhrmann)
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[ 5.278, 45.998, 0.08], // 32 Capella
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[ 5.992, 44.947, 1.90], // 33 Menkalinan
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[ 5.995, 37.213, 2.65], // 34 Mahasim
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// Leo (Löwe)
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[10.140, 11.967, 1.35], // 35 Regulus
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[11.818, 14.572, 2.14], // 36 Denebola
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[10.333, 19.842, 2.01], // 37 Algieba
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[11.235, 20.524, 2.56], // 38 Zosma
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[10.897, 25.000, 3.44], // 39 Adhafera
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[10.122, 23.774, 3.52], // 40 Rasalas
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// Boötes (Bärenhüter)
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[14.261, 19.182, -0.05], // 41 Arcturus
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[14.750, 27.074, 2.37], // 42 Izar
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[13.911, 18.398, 2.68], // 43 Muphrid
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[14.535, 38.308, 3.04], // 44 Seginus
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[15.032, 40.390, 3.49], // 45 Nekkar
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// Cygnus (Schwan / Nordkreuz)
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[20.691, 45.280, 1.25], // 46 Deneb
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[20.370, 40.257, 2.23], // 47 Sadr
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[20.770, 33.971, 2.48], // 48 Gienah (ε Cyg)
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[19.512, 27.960, 3.08], // 49 Albireo
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[19.749, 45.131, 2.87], // 50 δ Cyg
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// Lyra (Leier)
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[18.616, 38.784, 0.03], // 51 Vega
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[18.835, 33.363, 3.52], // 52 Sheliak
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[18.982, 32.690, 3.24], // 53 Sulafat
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// Aquila (Adler)
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[19.846, 8.868, 0.77], // 54 Altair
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[19.771, 10.613, 2.72], // 55 Tarazed
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[19.922, 6.407, 3.71], // 56 Alshain
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// Scorpius (Skorpion)
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[16.490,-26.432, 0.96], // 57 Antares
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[17.560,-37.104, 1.62], // 58 Shaula
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[17.622,-42.998, 1.86], // 59 Sargas
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[16.006,-22.622, 2.29], // 60 Dschubba
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[15.931,-19.805, 2.62], // 61 Graffias
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[17.531,-37.298, 2.69], // 62 Lesath
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// Sagittarius (Schütze / Teekanne)
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[18.403,-34.385, 1.85], // 63 Kaus Australis
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[18.921,-26.297, 2.02], // 64 Nunki
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[18.350,-29.828, 2.70], // 65 Kaus Media
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[18.345,-25.422, 2.81], // 66 Kaus Borealis
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[18.466,-25.422, 2.89], // 67 Ascella
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// Pegasus (Geflügeltes Pferd)
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[23.079, 15.205, 2.49], // 68 Markab
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[23.063, 28.083, 2.42], // 69 Scheat
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[ 0.221, 15.184, 2.83], // 70 Algenib
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[21.736, 9.875, 2.38], // 71 Enif
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[22.691, 10.832, 2.83], // 72 Homam
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// Andromeda
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[ 0.140, 29.091, 2.07], // 73 Alpheratz (auch Pegasus-Ecke)
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[ 1.162, 35.620, 2.07], // 74 Mirach
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[ 2.065, 42.330, 2.10], // 75 Almach
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// Perseus
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[ 3.405, 49.861, 1.79], // 76 Mirfak
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[ 3.136, 40.957, 2.12], // 77 Algol
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[ 3.902, 31.884, 2.85], // 78 Atik
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// Aries (Widder)
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[ 2.120, 23.462, 2.01], // 79 Hamal
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[ 1.911, 20.808, 2.64], // 80 Sheratan
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// Virgo (Jungfrau)
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[13.420,-11.161, 0.97], // 81 Spica
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[12.694, -1.449, 2.74], // 82 Porrima
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[13.036, 10.959, 2.83], // 83 Vindemiatrix
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// Canis Major (Großer Hund)
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[ 6.753,-16.716, -1.46], // 84 Sirius
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[ 6.977,-28.972, 1.50], // 85 Adhara
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[ 7.140,-26.393, 1.84], // 86 Wezen
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[ 6.378,-17.956, 1.98], // 87 Mirzam
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// Canis Minor (Kleiner Hund)
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[ 7.655, 5.225, 0.38], // 88 Procyon
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[ 7.453, 8.289, 2.90], // 89 Gomeisa
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// Draco (Drache)
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[17.943, 51.489, 2.23], // 90 Eltanin
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[17.507, 52.301, 2.79], // 91 Rastaban
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[16.400, 61.514, 3.29], // 92 Altais
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// Corona Borealis (Nördliche Krone)
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[15.578, 26.715, 2.21], // 93 Alphecca
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[15.464, 29.106, 3.66], // 94 Nusakan
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[15.700, 26.296, 3.84], // 95 γ CrB
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// Hercules (Herkules)
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[16.504, 21.490, 2.77], // 96 Kornephoros
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[16.688, 31.602, 2.81], // 97 Zeta Her
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[17.258, 36.809, 3.16], // 98 Pi Her
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[16.714, 38.922, 3.48], // 99 Eta Her
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// Ophiuchus / Schlangenträger
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[17.582, 12.560, 2.08], // 100 Rasalhague
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[16.619, 9.375, 2.43], // 101 Sabik
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];
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/* ── Sternbild-Linien ──────────────────────────
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Paare [von, bis] als Indizes in CAT
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─────────────────────────────────────────────── */
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const LINES = [
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// Orion
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[0, 2], [2, 3], [3, 4], [4, 5], [5, 0], // Körper (Schultern→Gürtel→zurück)
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[3, 1], [5, 6], // Beine (Mintaka→Rigel, Alnitak→Saiph)
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// Ursa Major – Großer Wagen
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[7, 8], [8, 9], [9, 10], [10, 7], // Kastenrahmen
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[10, 11], [11, 12], [12, 13], // Deichsel
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// Ursa Minor – Kleiner Wagen
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[14, 15], [15, 16],
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// Cassiopeia – W
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[17, 18], [18, 19], [19, 20], [20, 21],
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// Gemini – Zwillinge
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[22, 23], // Pollux-Castor (Köpfe)
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[22, 25], [25, 24], // Pollux-Körper
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[23, 26], [26, 27], // Castor-Körper
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// Taurus – Stier
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[28, 31], [28, 29], // Hyaden V + Horn Elnath
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[30, 28], // Pleiaden → Aldebaran
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// Auriga – Fuhrmann (Pentagon)
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[32, 33], [33, 34], [34, 29], [29, 32],
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// Leo – Löwe (Sichel + Körper)
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[35, 37], [37, 39], [39, 40], [40, 35], // Sichel / Kopf
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[37, 38], [38, 36], // Körper → Denebola
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// Boötes – Bärenhüter
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[41, 43], [41, 42], [42, 44], [44, 45],
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// Cygnus – Schwan / Nordsternkreuz
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[46, 47], [47, 49], // Längsbalken Deneb→Albireo
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[48, 47], [47, 50], // Querbalken
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// Lyra – Leier
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[51, 52], [52, 53], [53, 51],
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// Aquila – Adler
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[55, 54], [54, 56],
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// Scorpius – Skorpion
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[61, 60], [60, 57], // Kopf → Antares
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[57, 65], [65, 63], [63, 62], [62, 58], // Schwanz
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// Sagittarius – Teekanne
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[66, 65], [65, 63], [63, 67], [67, 64],
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[64, 66],
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// Pegasus – Großes Quadrat
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[68, 69], [69, 73], [73, 70], [70, 68],
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[71, 72], [72, 68], // Enif (Pferdekopf)
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// Andromeda
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[73, 74], [74, 75],
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// Perseus
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[76, 77], [76, 78],
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// Aries – Widder
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[79, 80],
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// Virgo – Jungfrau
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[81, 82], [82, 83],
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// Canis Major
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[84, 87], [84, 85], [85, 86],
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// Canis Minor
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[88, 89],
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// Draco – Drache (Kopf)
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[90, 91], [91, 92],
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// Corona Borealis – Nördliche Krone
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[94, 93], [93, 95],
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// Hercules – Schlüsselstein
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[96, 97], [97, 99], [99, 98], [98, 96],
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// Ophiuchus
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[100, 101],
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];
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/* ── Hintergrund: zufällige Sterne (RA/Dek kugelverteilt) ── */
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const BG = Array.from({ length: 350 }, () => ({
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ra: Math.random() * 24,
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dec: Math.asin(Math.random() * 2 - 1) * 180 / Math.PI,
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mag: 3.8 + Math.random() * 2.2,
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ph: Math.random() * Math.PI * 2,
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tw: 2500 + Math.random() * 5000,
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}));
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/* ── Canvas ─────────────────────────────────── */
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const canvas = document.getElementById('stars');
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if (!canvas) return;
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const ctx = canvas.getContext('2d');
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let W, H;
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function resize() {
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W = canvas.width = window.innerWidth;
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H = canvas.height = window.innerHeight;
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}
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/* ── Lokale Sternzeit (LST) ─────────────────── */
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function getLST(d) {
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const jd = d.getTime() / 86400000 + 2440587.5;
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const T = (jd - 2451545.0) / 36525;
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let gmst = (6.697374558 + 2400.0513369 * T + 0.0000258622 * T * T) % 24;
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if (gmst < 0) gmst += 24;
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const ut = d.getUTCHours() + d.getUTCMinutes() / 60 + d.getUTCSeconds() / 3600;
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return ((gmst + ut * 1.00273790935 + LON / 15) % 24 + 24) % 24;
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}
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/* ── Höhe über Horizont (Grad) ──────────────── */
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function altitude(ra, dec, lst) {
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const H = (lst - ra) * 15 * Math.PI / 180;
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const dRad = dec * Math.PI / 180;
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const lRad = LAT * Math.PI / 180;
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const sinA = Math.sin(dRad) * Math.sin(lRad) + Math.cos(dRad) * Math.cos(lRad) * Math.cos(H);
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return Math.asin(Math.max(-1, Math.min(1, sinA))) * 180 / Math.PI;
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}
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/* ── Projektion: äquatorial flach ──────────────
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LST steht im Bildzentrum (Meridian = Mitte)
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Dek 25° im vertikalen Zentrum
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12 Stunden RA sichtbar (halber Himmel)
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─────────────────────────────────────────────── */
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const REF_DEC = 25;
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function project(ra, dec, lst) {
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let dRA = lst - ra;
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if (dRA > 12) dRA -= 24;
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if (dRA < -12) dRA += 24;
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const pph = W / 12; // Pixel pro Stunde RA
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const ppd = pph / 15; // Pixel pro Grad Dek
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return {
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x: W / 2 + dRA * pph,
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y: H / 2 - (dec - REF_DEC) * ppd,
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};
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}
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/* ── Sternradius aus Magnitude ──────────────── */
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function magR(m) {
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return Math.max(0.4, 3.5 - m * 0.65);
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}
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/* ── Zeichnen ───────────────────────────────── */
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function draw(time) {
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ctx.clearRect(0, 0, W, H);
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const lst = getLST(new Date());
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const pad = 30;
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/* 1 · Hintergrund-Sterne */
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for (const s of BG) {
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const alt = altitude(s.ra, s.dec, lst);
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if (alt < -8) continue;
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const p = project(s.ra, s.dec, lst);
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if (p.x < -pad || p.x > W + pad || p.y < -pad || p.y > H + pad) continue;
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const twinkle = 0.35 + 0.55 * (0.5 + 0.5 * Math.sin(time / s.tw + s.ph));
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const horizFade = alt < 0 ? Math.max(0, 1 + alt / 8) : 1;
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ctx.beginPath();
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ctx.arc(p.x, p.y, magR(s.mag), 0, Math.PI * 2);
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ctx.fillStyle = `rgba(210,225,255,${(twinkle * horizFade * 0.4).toFixed(3)})`;
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ctx.fill();
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}
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/* 2 · Sternbild-Linien */
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ctx.lineWidth = 0.7;
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for (const [a, b] of LINES) {
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const [raA, decA] = CAT[a];
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const [raB, decB] = CAT[b];
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const altA = altitude(raA, decA, lst);
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const altB = altitude(raB, decB, lst);
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if (altA < -8 && altB < -8) continue;
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const pa = project(raA, decA, lst);
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const pb = project(raB, decB, lst);
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if (Math.abs(pa.x - pb.x) > W * 0.55) continue; // RA-Wrap überspringen
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const fade = Math.max(0, Math.min(1, (Math.max(altA, altB) + 5) / 15));
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ctx.strokeStyle = `rgba(200,168,75,${(fade * 0.14).toFixed(3)})`;
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ctx.beginPath();
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ctx.moveTo(pa.x, pa.y);
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ctx.lineTo(pb.x, pb.y);
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ctx.stroke();
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}
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/* 3 · Katalog-Sterne (Hellsterne) */
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for (const [ra, dec, mag] of CAT) {
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const alt = altitude(ra, dec, lst);
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if (alt < -6) continue;
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const p = project(ra, dec, lst);
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if (p.x < -pad || p.x > W + pad || p.y < -pad || p.y > H + pad) continue;
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const horizFade = alt < 5 ? Math.max(0.08, (alt + 6) / 11) : 1;
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const twinkle = 0.8 + 0.2 * Math.sin(time / 1600 + ra * 0.7);
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const alpha = Math.min(1, horizFade * twinkle);
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const r = magR(mag);
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// Leuchthof für Sterne heller als mag 2
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if (mag < 2.0) {
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const glowR = r * (mag < 0.5 ? 6 : mag < 1.0 ? 5 : 4);
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const glow = ctx.createRadialGradient(p.x, p.y, 0, p.x, p.y, glowR);
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glow.addColorStop(0, `rgba(220,235,255,${(alpha * 0.28).toFixed(3)})`);
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glow.addColorStop(1, 'rgba(220,235,255,0)');
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ctx.beginPath();
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ctx.arc(p.x, p.y, glowR, 0, Math.PI * 2);
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ctx.fillStyle = glow;
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ctx.fill();
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}
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ctx.beginPath();
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ctx.arc(p.x, p.y, r, 0, Math.PI * 2);
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ctx.fillStyle = `rgba(235,242,255,${alpha.toFixed(3)})`;
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ctx.fill();
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}
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requestAnimationFrame(draw);
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}
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window.addEventListener('resize', resize);
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resize();
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requestAnimationFrame(draw);
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})();
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