Coordinated Lunar Time sizinthu zomwe zimali mu malingaliro yokha — lingathe kuwerengetsa lero kugwiritsira ntchito physics ndi astronomy zomwe zimangako. Nkhani iyi ikufotokozera masamu yomwe ndi kumbuyo kwa live LTC clock pa moontimenow.com, kuchokera kwa reference epoch mpaka algorithm ya Meeus yomwe iyezeledwa magawo a mwezi.
J2000.0 Reference Epoch
System yonse ya nthawi ifuna malo oyambira. Kwa kuwerengeka kwa lunar time, timagwiritsira ntchito J2000.0 epoch: Chezamtanda 1, 2000 pa 12:00:00 UTC (madzulo). Umu ndi standard astronomical reference epoch yomwe imagwiritsidwa ntchito ndi NASA, ESA, ndi astronomers mdziko lonse.
J2000.0 imafanana ndi Julian Date 2451545.0. Pothetsa kuchuluka kwa masiku omwe anapitilira kuyambira epoch iyi, tingathe kuwerengeka kopongeza kwa kulosera kwa ma lokasi pa Mwezi kuposa kwa Earth's.
Formula ya Drift Rate
Kuwerengeka kwa mzere ndi kosavuta. Nthawi ya relativistic drift ndi +56.02 microseconds pa tsiku lililonse la Earth. Kuti tipeze kulosera kokonkozane pa nthawi iliyonse:
1. Kuwerengeka kuchuluka kwa masiku kuyambira J2000.0 (ziphatikizidwe ndi fractional days) 2. Kuchulukitsa ndi 56.02 microseconds 3. Wonjezera offset iyi kwa UTC nthawi yomwe ili pa lero
Kwa chitsanzo, pa Chezamtanda 1, 2025, pamwamba pa masiku 9,131 anapitilira kuyambira J2000.0. Kulosera kokonkozane ndi 9,131 × 56.02 = 511,418.62 microseconds, kapena pamwamba pa 0.511 sekondi.
Drift rate yeniyeni imachokera mu kusiyana kwa gravitational potential pakati pa Earth ndi Mwezi, yokonzeketsedwa kwa orbital velocity effects. NIST's 2024 framework paper ikufotokozera full derivation.
ΔT — Earth Rotation Correction
Pali zovuta mu conversion pakati pa astronomical time ndi civil time. Astronomers amagwira Terrestrial Time (TT), yomwe imayenda ndi kulondeza, pamene ma lokasi athu amagwiritsira UTC, yomwe imaphatikizira leap seconds kuti ikudzikala kwa Earth's rotation yomwe ndi yosinthasintha pang'ono.
Zoyika pakati pa TT ndi UTC chitchedwa ΔT (Delta T). Kwa nthawi iyi (2015–2035), ΔT ndi pamwamba pa 69.36 sekondi ndipo imasinthasintha pang'ono — pamwamba pa −0.06 sekondi pa chaka. Kuwerengeka kwathu kumagwiritsira ntchito polynomial fit kwa International Earth Rotation Service (IERS) data:
ΔT ≈ 69.36 − 0.06 × (chaka − 2020)
Correction iyi imakusumusiza kuti lunar time yomwe ikuwonetsedwa pa clock yathu ndi yokulungamitsa ndi UTC nthawi yomwe ikuwonetsedwa pa locket yanu yomwe yali ndi chidziwitsochi.
Moon Phase Calculation — Meeus Algorithm
Moon phase calendar imagwiritsira ntchito algorithm ya Jean Meeus kuchokera Astronomical Algorithms (Chapter 49). Njira iyi iyezeledwa nthawi zeniyeni za new moons, full moons, ndi quarter moons kugwiritsira ntchito nthawi 25 zomwe zimukumveramukanso zomwe zidapangidwa kuchokera kwa orbital mechanics yomwe ili ndi zovuta ya Mwezi.
Algorithm imagwira pothetsa lunation number yomwe ndi approximation (k) kwa tsiku lilililonse, ndipo iwonjezera trigonometric corrections zomwe zimadala kwa Moon's mean anomaly, Sun's mean anomaly, Moon's argument of latitude, ndi longitude ya ascending node.
Tables zosiyanasiyana za correction zimagwiritsidwa ntchito kwa new moons (Table 49.a), full moons (Table 49.b), ndi quarter moons (Table 49.c/d ndi W correction term). Zomwe zimapangidwa zili ndi kulondeza pa ~2 maminiti kwinanzo kwa U.S. Naval Observatory data.
Illumination ndi Phase Names
Pakati pa magawo akuluakulu, kuwala kwa Mwezi kumawerengetsa kugwiritsira ntchito piecewise interpolation pakati pa nthawi za quarter zomwe zapezeka ndi chidziwitsochi. Njira iyi imawerengetsa Mwezi's varying orbital speed (imayenda mabwinobwino pa perigee, pang'ono pa apogee), kupela kulondeza kokulutsa kwa illumination percentages kuposa simple sinusoidal approximation.
Phase names zimapatsidwa kudzimire kumbuyo kwa position mu lunation cycle: New Moon → Waxing Crescent → First Quarter → Waxing Gibbous → Full Moon → Waning Gibbous → Last Quarter → Waning Crescent. Phase boundaries zimakutalikirana kwa calculated phase times osati fixed fractional positions.