{"id":"vidhyamitra:city-day:chicago:1981-05-18:en","page_class":"VM-CD-city-day","url":"https://vidhyamitra.com/city/chicago/1981-05-18","language":{"target_lang":"en","base_lang":"en","quality_tier":"canonical"},"data":{"date":"1981-05-18","date_display":"May 18, 1981 CE","panchanga":{"method":"Sūrya Siddhānta + Bhāskara-II iterative manda + Kerala-school (Mādhava-Nīlakaṇṭha) evection + variation + annual equation","engine_version":"2.0 (Kerala-school enhanced)","accuracy_note":"Sub-degree on Moon at any Kali-Yuga date (~2-5° residual max)","tradition_chain":"Āryabhaṭa(499) → Brahmagupta(628) → Bhāskara II(1150) → Mādhava(~1400) → Parameśvara(1430) → Nīlakaṇṭha(1501) → this","input":{"year":1981,"month":5,"day":18,"hour":6,"minute":30,"second":0,"calendar":"gregorian"},"julian_day":2444742.770833,"kali_year":5083,"ahargana":1856277.2708,"sun":{"sidereal_longitude":33.439,"rashi":2,"rashi_name":"Vṛṣabha"},"moon":{"sidereal_longitude":203.0301,"rashi":7,"rashi_name":"Tulā"},"tithi":{"number":15,"name":"Pūrṇimā","paksha":"Śukla","full_name":"Śukla Pūrṇimā","elongation_degrees":169.5911,"elapsed_within_tithi_degrees":1.5911},"nakshatra":{"number":16,"name":"Viśākhā","pada":1,"moon_longitude":203.0301,"elapsed_within_degrees":3.0301},"yoga":{"number":18,"name":"Varīyān","sum_longitude":236.4692},"karana":{"half_tithi_index":28,"name":"Viṣṭi"},"vara":{"number":3,"name":"Somavāra (Monday)"}},"sky":{"method":"Sūrya-Siddhāntic Bhāskara-II 4-step iteration with atan2-based śīghra + varying peripheries + lunar latitude","engine_version":"3.0 (Pūrṇa — complete SS implementation)","tradition_sources":"Āryabhaṭīya 499 CE → SS Ch.1-5 Burgess 1860 → Siddhānta-Śiromaṇi Bhāskara II 1150 → Tantrasaṅgraha Nīlakaṇṭha 1501","input":{"year":1981,"month":5,"day":18,"hour":6,"minute":30,"calendar":"gregorian"},"julian_day":2444742.770833,"ahargana":1856277.2708,"kali_year":5083,"ayanamsa_lahiri":23.5928,"grahas":{"sun":{"sidereal_longitude":33.431906000000026,"rashi":{"number":2,"name":"Vṛṣabha"},"nakshatra":{"number":3,"name":"Kṛttikā","pada":3},"retrograde":false},"moon":{"sidereal_longitude":202.992206,"rashi":{"number":7,"name":"Tulā"},"nakshatra":{"number":16,"name":"Viśākhā","pada":1},"retrograde":false,"latitude":4.4611},"mars":{"sidereal_longitude":23.501105999999993,"rashi":{"number":1,"name":"Meṣa"},"nakshatra":{"number":2,"name":"Bharaṇī","pada":4},"retrograde":false},"mercury":{"sidereal_longitude":53.91680600000001,"rashi":{"number":2,"name":"Vṛṣabha"},"nakshatra":{"number":5,"name":"Mr̥gaśirā","pada":1},"retrograde":false},"jupiter":{"sidereal_longitude":157.16290600000002,"rashi":{"number":6,"name":"Kanyā"},"nakshatra":{"number":12,"name":"Uttara Phalgunī","pada":4},"retrograde":true},"venus":{"sidereal_longitude":44.329206,"rashi":{"number":2,"name":"Vṛṣabha"},"nakshatra":{"number":4,"name":"Rohiṇī","pada":2},"retrograde":false},"saturn":{"sidereal_longitude":159.44000600000004,"rashi":{"number":6,"name":"Kanyā"},"nakshatra":{"number":12,"name":"Uttara Phalgunī","pada":4},"retrograde":true},"rahu":{"sidereal_longitude":105.4972,"rashi":{"number":4,"name":"Karka"},"nakshatra":{"number":8,"name":"Puṣya","pada":4},"retrograde":false},"ketu":{"sidereal_longitude":285.4972,"rashi":{"number":10,"name":"Makara"},"nakshatra":{"number":22,"name":"Śravaṇa","pada":2},"retrograde":false}},"panchang":{"method":"Sūrya Siddhānta + Bhāskara-II iterative manda + Kerala-school (Mādhava-Nīlakaṇṭha) evection + variation + annual equation","engine_version":"2.0 (Kerala-school enhanced)","accuracy_note":"Sub-degree on Moon at any Kali-Yuga date (~2-5° residual max)","tradition_chain":"Āryabhaṭa(499) → Brahmagupta(628) → Bhāskara II(1150) → Mādhava(~1400) → Parameśvara(1430) → Nīlakaṇṭha(1501) → this","input":{"year":1981,"month":5,"day":18,"hour":6,"minute":30,"second":0,"calendar":"gregorian"},"julian_day":2444742.770833,"kali_year":5083,"ahargana":1856277.2708,"sun":{"sidereal_longitude":33.439,"rashi":2,"rashi_name":"Vṛṣabha"},"moon":{"sidereal_longitude":203.0301,"rashi":7,"rashi_name":"Tulā"},"tithi":{"number":15,"name":"Pūrṇimā","paksha":"Śukla","full_name":"Śukla Pūrṇimā","elongation_degrees":169.5911,"elapsed_within_tithi_degrees":1.5911},"nakshatra":{"number":16,"name":"Viśākhā","pada":1,"moon_longitude":203.0301,"elapsed_within_degrees":3.0301},"yoga":{"number":18,"name":"Varīyān","sum_longitude":236.4692},"karana":{"half_tithi_index":28,"name":"Viṣṭi"},"vara":{"number":3,"name":"Somavāra (Monday)"}},"eclipse_current":{"solar":{"type":"solar","occurs":false,"moon_latitude":4.461,"elongation":169.591},"lunar":{"type":"lunar","occurs":false,"moon_latitude":4.461,"opposition_distance":10.409}},"eclipse_window_40days":[]},"city":{"slug":"chicago","name":"Chicago, USA","lat":41.8781,"lon":-87.6298,"tz_offset_hours":-6,"country":"US","tier":"diaspora"},"tier2":{"city":{"slug":"chicago","name":"Chicago, USA","lat":41.8781,"lon":-87.6298,"tz_offset_hours":-6,"country":"US","tier":"diaspora"},"sunriseLocal":"04:28","sunsetLocal":"19:06","solarNoonLocal":"11:47","dayLengthHours":14.634361613912652,"dayLengthDisplay":"14 Hours 38 Mins 04 Secs","nightLengthDisplay":"9 Hours 21 Mins 56 Secs","moonriseLocal":"18:04","moonsetLocal":"04:06","rahuKala":{"name":"Rāhu Kāla","start":"06:18","end":"08:07","startHours":6.2926146916082635,"endHours":8.121909893347345,"quality":"inauspicious"},"yamaganda":{"name":"Yamaganda","start":"09:57","end":"11:47","startHours":9.951205095086426,"endHours":11.780500296825508,"quality":"inauspicious"},"gulika":{"name":"Gulika Kāla","start":"13:37","end":"15:26","startHours":13.60979549856459,"endHours":15.439090700303671,"quality":"inauspicious"},"durMuhurta":[{"name":"Dur Muhūrta","start":"07:53","end":"08:22","startHours":7.8780038664488,"endHours":8.36581592024589,"quality":"avoid"}],"varjyam":{"name":"Varjyam","start":"05:04","end":"05:28","startHours":5.073084557115543,"endHours":5.463334200153214,"quality":"avoid"},"abhijit":{"name":"Abhijit Muhūrta","start":"11:18","end":"12:16","startHours":11.29268824302842,"endHours":12.268312350622596,"quality":"auspicious"},"brahmaMuhurta":{"name":"Brahma Muhūrta","start":"02:31","end":"03:29","startHours":2.512071274680828,"endHours":3.487695382275005,"quality":"auspicious"},"pratahSandhya":{"name":"Prātaḥ Sandhyā","start":"03:15","end":"04:28","startHours":3.243789355376461,"endHours":4.463319489869182,"quality":"auspicious"},"vijayaMuhurta":{"name":"Vijaya Muhūrta","start":"14:13","end":"15:12","startHours":14.21956056581095,"endHours":15.195184673405127,"quality":"auspicious"},"godhuliMuhurta":{"name":"Godhūli Muhūrta","start":"18:54","end":"19:18","startHours":18.897681103781835,"endHours":19.297681103781834,"quality":"auspicious"},"sayahnaSandhya":{"name":"Sāyāhna Sandhyā","start":"19:06","end":"19:42","startHours":19.097681103781834,"endHours":19.707446171028195,"quality":"auspicious"},"amritKala":{"name":"Amṛta Kāla","start":"18:51","end":"20:36","startHours":18.847681103781834,"endHours":20.597681103781834,"quality":"auspicious"},"nishitaMuhurta":{"name":"Niśīta Muhūrta","start":"23:18","end":"00:16","startHours":23.29268824302842,"endHours":24.268312350622598,"quality":"auspicious"},"dayChoghadiyas":[{"name":"Amṛta","start":"04:28","end":"06:18","startHours":4.463319489869182,"endHours":6.2926146916082635,"quality":"auspicious"},{"name":"Kāla","start":"06:18","end":"08:07","startHours":6.2926146916082635,"endHours":8.121909893347345,"quality":"inauspicious"},{"name":"Śubha","start":"08:07","end":"09:57","startHours":8.121909893347345,"endHours":9.951205095086426,"quality":"auspicious"},{"name":"Roga","start":"09:57","end":"11:47","startHours":9.951205095086426,"endHours":11.780500296825508,"quality":"inauspicious"},{"name":"Udveg","start":"11:47","end":"13:37","startHours":11.780500296825508,"endHours":13.60979549856459,"quality":"inauspicious"},{"name":"Chala","start":"13:37","end":"15:26","startHours":13.60979549856459,"endHours":15.439090700303671,"quality":"neutral"},{"name":"Labha","start":"15:26","end":"17:16","startHours":15.439090700303671,"endHours":17.268385902042752,"quality":"auspicious"},{"name":"Amṛta","start":"17:16","end":"19:06","startHours":17.268385902042752,"endHours":19.097681103781834,"quality":"auspicious"}],"nightChoghadiyas":[{"name":"Chala","start":"19:06","end":"20:16","startHours":19.097681103781834,"endHours":20.268385902042752,"quality":"neutral"},{"name":"Labha","start":"20:16","end":"21:26","startHours":20.268385902042752,"endHours":21.439090700303673,"quality":"auspicious"},{"name":"Amṛta","start":"21:26","end":"22:37","startHours":21.439090700303673,"endHours":22.60979549856459,"quality":"auspicious"},{"name":"Kāla","start":"22:37","end":"23:47","startHours":22.60979549856459,"endHours":23.780500296825508,"quality":"inauspicious"},{"name":"Śubha","start":"23:47","end":"00:57","startHours":23.780500296825508,"endHours":24.951205095086426,"quality":"auspicious"},{"name":"Roga","start":"00:57","end":"02:07","startHours":24.951205095086426,"endHours":26.121909893347343,"quality":"inauspicious"},{"name":"Udveg","start":"02:07","end":"03:18","startHours":26.121909893347343,"endHours":27.292614691608264,"quality":"inauspicious"},{"name":"Chala","start":"03:18","end":"04:28","startHours":27.292614691608264,"endHours":28.463319489869182,"quality":"neutral"}],"horas":[{"name":"Hora 1","start":"04:28","end":"05:28","startHours":4.463319489869182,"endHours":5.463319489869182,"planetary_lord":"Moon"},{"name":"Hora 2","start":"05:28","end":"06:28","startHours":5.463319489869182,"endHours":6.463319489869182,"planetary_lord":"Mercury"},{"name":"Hora 3","start":"06:28","end":"07:28","startHours":6.463319489869182,"endHours":7.463319489869182,"planetary_lord":"Venus"},{"name":"Hora 4","start":"07:28","end":"08:28","startHours":7.463319489869182,"endHours":8.463319489869182,"planetary_lord":"Sun"},{"name":"Hora 5","start":"08:28","end":"09:28","startHours":8.463319489869182,"endHours":9.463319489869182,"planetary_lord":"Mars"},{"name":"Hora 6","start":"09:28","end":"10:28","startHours":9.463319489869182,"endHours":10.463319489869182,"planetary_lord":"Jupiter"},{"name":"Hora 7","start":"10:28","end":"11:28","startHours":10.463319489869182,"endHours":11.463319489869182,"planetary_lord":"Saturn"},{"name":"Hora 8","start":"11:28","end":"12:28","startHours":11.463319489869182,"endHours":12.463319489869182,"planetary_lord":"Moon"},{"name":"Hora 9","start":"12:28","end":"13:28","startHours":12.463319489869182,"endHours":13.463319489869182,"planetary_lord":"Mercury"},{"name":"Hora 10","start":"13:28","end":"14:28","startHours":13.463319489869182,"endHours":14.463319489869182,"planetary_lord":"Venus"},{"name":"Hora 11","start":"14:28","end":"15:28","startHours":14.463319489869182,"endHours":15.463319489869182,"planetary_lord":"Sun"},{"name":"Hora 12","start":"15:28","end":"16:28","startHours":15.463319489869182,"endHours":16.463319489869182,"planetary_lord":"Mars"},{"name":"Hora 13","start":"16:28","end":"17:28","startHours":16.463319489869182,"endHours":17.463319489869182,"planetary_lord":"Jupiter"},{"name":"Hora 14","start":"17:28","end":"18:28","startHours":17.463319489869182,"endHours":18.463319489869182,"planetary_lord":"Saturn"},{"name":"Hora 15","start":"18:28","end":"19:28","startHours":18.463319489869182,"endHours":19.463319489869182,"planetary_lord":"Moon"},{"name":"Hora 16","start":"19:28","end":"20:28","startHours":19.463319489869182,"endHours":20.463319489869182,"planetary_lord":"Mercury"},{"name":"Hora 17","start":"20:28","end":"21:28","startHours":20.463319489869182,"endHours":21.463319489869182,"planetary_lord":"Venus"},{"name":"Hora 18","start":"21:28","end":"22:28","startHours":21.463319489869182,"endHours":22.463319489869182,"planetary_lord":"Sun"},{"name":"Hora 19","start":"22:28","end":"23:28","startHours":22.463319489869182,"endHours":23.463319489869182,"planetary_lord":"Mars"},{"name":"Hora 20","start":"23:28","end":"00:28","startHours":23.463319489869182,"endHours":24.463319489869182,"planetary_lord":"Jupiter"},{"name":"Hora 21","start":"00:28","end":"01:28","startHours":24.463319489869182,"endHours":25.463319489869182,"planetary_lord":"Saturn"},{"name":"Hora 22","start":"01:28","end":"02:28","startHours":25.463319489869182,"endHours":26.463319489869182,"planetary_lord":"Moon"},{"name":"Hora 23","start":"02:28","end":"03:28","startHours":26.463319489869182,"endHours":27.463319489869182,"planetary_lord":"Mercury"},{"name":"Hora 24","start":"03:28","end":"04:28","startHours":27.463319489869182,"endHours":28.463319489869182,"planetary_lord":"Venus"}],"taraBala":{"favorable_nakshatras":["Aśvinī","Bharaṇī","Kṛttikā","Puṣya","Aśleṣā","Maghā","Pūrva Phalgunī","Uttara Phalgunī","Anurādhā","Jyeṣṭhā","Mūla","Pūrva Āṣāḍhā","Uttara Āṣāḍhā","Uttara Bhādrapadā","Revatī"],"unfavorable_nakshatras":["Rohiṇī","Mṛgaśirā","Ārdrā","Punarvasu","Hasta","Citrā","Svātī","Viśākhā","Śravaṇa","Dhaniṣṭhā","Śatabhiṣaj","Pūrva Bhādrapadā"],"nature":"Janma-tara if same nakshatra; favorable for 15 nakshatras"},"chandraBala":{"favorable_rashis":["Meṣa","Karka","Siṃha","Tulā","Dhanu","Mīna"],"unfavorable_rashis":["Vṛṣabha","Mithuna","Kanyā","Vṛścika","Makara","Kumbha"]},"dishaShool":"East (Pūrva)","chandraVasa":"North","rahuVasa":"North-East","anandadiYoga":{"name":"Śubha","quality":"Auspicious"},"tropicalRitu":"Vasanta (Spring)","vedicRitu":"Vasanta (Spring)","tropicalAyana":"Uttarāyaṇa","vedicAyana":"Uttarāyaṇa","meta":{"method":"BOB-History Sūrya-Siddhānta + Vidhyamitra Tier-2 spherical localization","declination":19.49106684363513,"eotMinutes":3.6891821904695723,"ayanamsa":23.5928}},"calendars":{"vikram_samvat":2038,"vikram_samvatsara":"Bhāva","saka_samvat":1903,"saka_samvatsara":"Durmati","bengali_samvat":1388,"malayalam_era":1157,"nanakshahi_year":512,"lunar_month":"Vaiśākha","lunar_month_paksha_full":"Vaiśākha Śukla Pakṣa","lunar_month_system":"purnimanta","lunar_month_purnimanta":"Vaiśākha","lunar_month_amanta":"Vaiśākha","lunar_month_is_adhika":false,"lunar_month_purnimanta_is_adhika":false,"lunar_month_amanta_is_adhika":false,"solar_month":"Vṛṣabha (Vaikāsi)","ritu":"Vasanta (Spring)","display_summary":"Vaiśākha Śukla Pūrṇimā · Vikram 2038 Bhāva · Śaka 1903 Durmati"},"festivals":[{"id":"buddha-purnima","name":"Buddha Pūrṇimā","name_sanskrit":"बुद्ध पूर्णिमा","name_alternates":["Vesak","Vaiśākhī Pūrṇimā","Vesakha"],"tradition":"Pan-Hindu","associated_deity":"Buddha (21st avatāra of Krishna per Bhāgavata 1.3.24)","deity_avatara_index":21,"significance":"Buddha's birth, enlightenment, and mahāparinirvāṇa all on this Vaiśākha Pūrṇimā. Most sacred Buddhist + Vaishnava day.","vrata":true,"primary_observance":"Day-long observance of compassion (karuṇā) and ahiṁsā; Buddha-stuti at sunset","detection":{"tithi_number":15,"tithi_paksha":"Śukla","lunar_month":"Vaiśākha"},"precedence":1,"related_chart":"buddha","historical_anchor":{"event":"Bhagavān Buddha's birth at Lumbinī","date_julian":"-0562-04-11","location":"Lumbinī, Nepal"},"sources":["Bhāgavata Purāṇa 1.3.24","Pāli Tipiṭaka","Buddhacarita by Aśvaghoṣa"]},{"id":"kurma-jayanti","name":"Kūrma Jayantī","name_sanskrit":"कूर्म जयन्ती","tradition":"Vaishnava","associated_deity":"Kūrma (2nd avatāra of Krishna)","deity_avatara_index":11,"significance":"Kūrma supports Mount Mandara during the Sāgara-mathana (churning of the cosmic ocean).","vrata":false,"detection":{"tithi_number":15,"tithi_paksha":"Śukla","lunar_month":"Vaiśākha"},"precedence":4,"sources":["Bhāgavata 8.7-8"]},{"id":"chandika-jayanti","name":"Chaṇḍikā Jayantī","name_sanskrit":"चण्डिका जयन्ती","tradition":"Shakta","associated_deity":"Devī Chaṇḍikā","significance":"Devī's fierce protective form. Often coincides with Buddha Pūrṇimā.","vrata":false,"detection":{"tithi_number":15,"tithi_paksha":"Śukla","lunar_month":"Vaiśākha"},"precedence":5},{"id":"chitra-paurnami","name":"Citrā Paurṇamī","name_sanskrit":"चित्रा पौर्णमी","tradition":"Regional","significance":"Tamil regional Vaiśākha Pūrṇimā observance; honors Citragupta.","vrata":false,"detection":{"tithi_number":15,"tithi_paksha":"Śukla","lunar_month":"Vaiśākha"},"precedence":6},{"id":"vaishakha-purnima-vrat","name":"Vaiśākha Pūrṇimā Vrat","name_sanskrit":"वैशाख पूर्णिमा व्रत","tradition":"Pan-Hindu","significance":"General Pūrṇimā vrat in Vaiśākha (highly auspicious month).","vrata":true,"detection":{"tithi_number":15,"tithi_paksha":"Śukla","lunar_month":"Vaiśākha"},"precedence":7}],"todays_walk":{"walk":{"id":"buddha-purnima-walk","name":"Buddha Pūrṇimā Walk","name_sanskrit":"बुद्ध पूर्णिमा यात्रा","type":"festival","description":"Bhāgavata 1.3.24 (Buddha as 21st avatāra) + BG 12.13 (compassion) + Dhammapada parallels.","step_count":7,"url":"/walk/buddha-purnima-walk"},"reason":"Today is Buddha Pūrṇimā — its dedicated walk."},"cosmic_resonances":[{"historical_date":"-0562-04-11","event":"Bhagavān Buddha's birth at Lumbinī","chart_id":"buddha","shared_marker":"same Śukla Pūrṇimā + Viśākhā","url":"/day/-0562-04-11","relevance":1},{"historical_date":"-3137-10-04","event":"Mahābhārata Day 1 (Bhagavad Gītā delivered)","chart_id":"krishna","shared_marker":"same Śukla Pūrṇimā","url":"/day/-3137-10-04","relevance":0.5}]},"validity":{"eternal":false,"location_specific":"chicago"},"liturgical":{"opening":"जय श्री कृष्ण","closing":"ॐ तत् सत्","attribution":"Computed by Vidhyamitra Sūrya-Siddhānta substrate + Vidhyamitra Tier-2 layer"},"seo":{"title":"Pañchāṅga May 18, 1981 CE · Chicago, USA · Vidhyamitra","description":"May 18, 1981 CE for Chicago, USA: Śukla Pūrṇimā, sūryodaya 04:28, sūryāsta 19:06.","schema_org_type":"Article","canonical":"https://vidhyamitra.com/city/chicago/1981-05-18","hreflang_alternates":{"en":"https://vidhyamitra.com/city/chicago/1981-05-18","sa":"https://sa.vidhyamitra.com/city/chicago/1981-05-18","hi":"https://hi.vidhyamitra.com/city/chicago/1981-05-18","x-default":"https://vidhyamitra.com/city/chicago/1981-05-18"}},"provenance":[{"pillar":"BOB-History","pillar_version":"2.12.0","method":"Sūrya-Siddhānta first-principles + Bhāskara II + Kerala-school (Mādhava-Nīlakaṇṭha) corrections","retrieved_at":"2026-06-02T15:41:26.348Z","verification":{"type":"multi-marker","confidence":"canonical"}},{"pillar":"Vidhyamitra-Tier2","pillar_version":"0.1.0","method":"Spherical astronomy + Lahiri ayanamsa + standard solar declination + EoT correction","retrieved_at":"2026-06-02T15:41:26.348Z","verification":{"type":"community-validated","markers":["modern-reference checked timing on Narasiṁha Jayantī 2026"],"confidence":"verified"}}],"meta":{"generated_at":"2026-06-02T15:41:26.348Z","pillar_versions":{"Sūrya-Siddhānta":"Pūrṇa","Vidhyamitra-Tier2":"Pūrṇa"}}}