इस महीने का हर वैदिक त्योहार, एकादशी, पूर्णिमा, अमावस्या और संक्रांति — पंचांग इंजन से लाइव गणना, दुर्लभता के हिसाब से बँटा, प्रमाण सहित। 89 कार्यक्रम: 1 बड़े, 34 मध्यम, 54 आवर्ती।
Narada Purana — Uttarardha, Ekadashi-vrata prakaranam, parana/dwadashi section'Yadi dvitiya din dvadashi hai to pehle din ki dashami-viddha ekadashi bhi niṣiddha hi hai (isliye aisi paristhiti mein dvadashi ko vrata karna chahiye).'
Narada Purana — Purvabhaga, karana-prakarana, verse 124Enumerates Shakuni, Naga, Chatushpada, Kimstughna as the four sthira (fixed) karanas of the lunar month.
रवि · अग 04
अमावस्या
Amavasya
मध्यम15:51 – 16:43amavasyanew_moonpitru
New moon, powerful for Tantric practices and pitru karma
Phaladeepika — Upagraha-prakarana (calculation of dhuma, vyatipata, parivesha, indrachapa, ketu), verse 5 (formula for vyatipata from solar position; Hindi-Alt ed., around lines 22701-22750)Vyatipata = (Sun + 4r 13°20') subtracted from 12 rashis — defined as 'a-prakasha-graha' (invisible graha).
Muhurta Chintamani — Shubhashubha Prakarana (karana enumeration), verses 23-24 (Pyarelal Mishra Hindi ed., lines 81-122 in muhurta_cintamani slug) — 'श्रीवत्साख्यो वज्रकं मुद्गरश्च ... चरसुस्थिराख्यप्रवर्धमानाः फलदाः स्वनाम्ना'Names all 11 karanas with their phala — Bava (chara, first) is the auspicious chara-karana for new beginnings; karanas grouped as 'phaladah svanama' (effects per their names).
Muhurta Chintamani — Shubhashubha Prakarana (karana enumeration), verses 23-24 (Pyarelal Mishra Hindi ed., lines 81-122 in muhurta_cintamani slug) — 'श्रीवत्साख्यो वज्रकं मुद्गरश्च ... चरसुस्थिराख्यप्रवर्धमानाः फलदाः स्वनाम्ना'Names all 11 karanas with their phala — Bava (chara, first) is the auspicious chara-karana for new beginnings; karanas grouped as 'phaladah svanama' (effects per their names).
Muhurta Chintamani — Shubhashubha Prakarana (karana enumeration), verses 23-24 (Pyarelal Mishra Hindi ed., lines 81-122 in muhurta_cintamani slug) — 'श्रीवत्साख्यो वज्रकं मुद्गरश्च ... चरसुस्थिराख्यप्रवर्धमानाः फलदाः स्वनाम्ना'Names all 11 karanas with their phala — Bava (chara, first) is the auspicious chara-karana for new beginnings; karanas grouped as 'phaladah svanama' (effects per their names).
Muhurta Chintamani — Nakshatra-prakarana (tyajya nakshatra and yoga), verse 34 (Pyarelal Mishra Hindi ed., lines 983-1007) — 'विष्कम्भवज्रवटिकात्रयमेव वर्ज्यम्'Vishkambha (with vajra) — first three vatikas (ghatikas) explicitly forbidden in shubha-karma; the yoga's name literally means 'obstruction'.
Sun enters a new rashi (solar ingress). All Sankrantis are considered punya kala. Sacred bath, surya arghya, tila dana, and charity are prescribed. The punya kala extends 16 ghatikas (~6.5 hours) before and after the exact transition moment.
Narada Purana — Uttarardha, Ekadashi-vrata prakaranam, parana/dwadashi section'Yadi dvitiya din dvadashi hai to pehle din ki dashami-viddha ekadashi bhi niṣiddha hi hai (isliye aisi paristhiti mein dvadashi ko vrata karna chahiye).'
शनि · अग 17
सिद्ध योग
Siddha Yoga
नियमित09:40 – 08:06siddhiauspicious
Accomplishment yoga, good for important beginnings
Thiruvonam -- the principal day of the ten-day Kerala harvest festival, falling on Shravana Nakshatra in the Malayalam solar month of Chingam (when the Sun is in Simha Rashi). The day commemorates the annual return of King Mahabali to visit his subjects; the Bhagavata Purana (8.15-23) records the Vamana avatara of Vishnu and the granting of this boon. Celebrations include the Onasadya feast, pookalam floral arrangements, and Vallam Kali boat races.
Muhurta Chintamani — Shubhashubha-prakarana, tyajya yoga section, verse 35Shula yoga's first 5 ghatikas explicitly enjoined for rejection in all karmas — especially travel.
Narada Purana — Purvabhaga, jataka-yoga-phala section, verses 195-196Shula-yoga jataka described as shura-vira but adhana (without wealth) — reinforces 'painful obstacles' theme.
Muhurta Chintamani — Shubhashubha Prakarana (karana enumeration), verses 23-24 (Pyarelal Mishra Hindi ed., lines 81-122 in muhurta_cintamani slug) — 'श्रीवत्साख्यो वज्रकं मुद्गरश्च ... चरसुस्थिराख्यप्रवर्धमानाः फलदाः स्वनाम्ना'Names all 11 karanas with their phala — Bava (chara, first) is the auspicious chara-karana for new beginnings; karanas grouped as 'phaladah svanama' (effects per their names).
गुरु · अग 29
सिद्ध योग
Siddha Yoga
नियमित01:20 – 01:38siddhiauspicious
Accomplishment yoga, good for important beginnings
Phaladeepika — Upagraha-prakarana (calculation of dhuma, vyatipata, parivesha, indrachapa, ketu), verse 5 (formula for vyatipata from solar position; Hindi-Alt ed., around lines 22701-22750)Vyatipata = (Sun + 4r 13°20') subtracted from 12 rashis — defined as 'a-prakasha-graha' (invisible graha).
शुक्र · अग 30
द्वादशी
Dwadashi
नियमित01:38 – 02:25dwadashivishnuparana
Parana (breaking Ekadashi fast) and Vishnu worship
Narada Purana — Uttarardha, Ekadashi-vrata prakaranam, parana/dwadashi section'Yadi dvitiya din dvadashi hai to pehle din ki dashami-viddha ekadashi bhi niṣiddha hi hai (isliye aisi paristhiti mein dvadashi ko vrata karna chahiye).'
शनि · अग 31
शनि पुष्य योग
Shani Pushya Yoga
मध्यम17:55 – 19:39pushyasaturnauspicious
Powerful for Saturn remedies, discipline, and iron/industry works
Muhurta Chintamani — Shubhashubha-prakaranam, verses 20-21 (vara-nakshatra niṣiddha chart)Muhurta Chintamani's vara-nakshatra table places Shani-Rohini in the niṣiddha set; the inverse Shani-Pushya is the canonically auspicious counterpart used in panchanga tradition for Saturn remedies and discipline-related works.
Verses 28-29 enumerate the full vara-nakshatra table (Sun: Hasta/Mula/Uttaraphalguni/Uttarashadha/Uttarabhadrapada/Pushya/Ashvini; Moon: Shravana/Rohini/Mrigashira/Pushya/Anuradha; Mars: Ashvini/Uttarabhadrapada/Krittika/Ashlesha; etc.) -- matches our table exactly.
(2)
Muhurta Chintamani — Samskara-prakarana (Pradosha-lakshana), verse 55 (Pyarelal Mishra Hindi ed., lines 3616-3650) — 'अर्कतर्कत्रितिथिषु प्रदोषः स्यात्'Defines pradosha-kala as the half-prahar around sunset on Trayodashi, Chaturdashi, Pratipad and other listed tithis.
Skanda Purana — Pradosha-vrata-mahatmya (Chandrasena and Shrikara legend), section on Pradosha-shivapujana (Sankshipta ed., lines 88951-89000)Anjananandana Hanuman teaches the gopa Shrikara the discipline of Pradosha Shiva worship.
Lists Sunday combined with Hasta, Mula, Uttaraphalguni, Uttarashada, Uttarabhadra, Pushya, Ashwini as Sarvarthasiddhi.
Muhurta Chintamani — Samvatsara-prakarana, Sun-avastha on Sankranti, verse 13Sun in Kimstughna karana described as 'urdhva' (upright, sama) — 'sama: shreshtha ihardhavarshane', i.e. neutral-to-mildly auspicious.
(2)
Skanda Purana — Pitri-kalpa / Tithi-pravachana, amavasya definition section'Yogon mein vyatipata, nakshatron mein shravana, tithiyon mein amavasya aur purnima tatha sankranti-kala -- ye sab dana-karma mein pavitra mane gaye hain.' Amavasya named first among agnishvattadi pitarana priya tithis.
Parashara Smriti — Madhaviya-vritti, Dana-kala-nirupana, Section on vyatipata as inauspicious yoga / sankrama (Islampurkar 1894 ed., around lines 40233-40259)Mahavyatipata defined; cited alongside ayana and vishuva as auspicious-dana times despite the yoga itself being inauspicious for new beginnings.
BPHS — Panchanga-sadhana / Karana-prakarana, standard BPHS section on the 11 karanas (Bava-Balava-Kaulava ... Naga-Kimstughna)BPHS lists the chara-karanas (Bava through Vishti) as repeated 8 times across the 30 tithi-halves; Bava is the first and most auspicious.
Narada Purana — Purvabhaga, Dvitiya-vrata section (Ashunyashayana-vrata), month-wise Dvitiya-vrata (Sankshipta ed., lines 65701-65750) — 'अशुन्यशयन ... चन्द्रमाके लिये अर्घ्यदान'Shravana-Krishna Dvitiya = Ashunyashayana-vrata to Vishnu-Lakshmi with chandra-arghya; Kartika-shukla Dvitiya = Yamadvitiya.
'Yam, Vishvedeva, Chandra, Brahma, Guru, Chandra, Indra, Jala, Sarpa, Agni, Surya, Bhumi, Rudra, Brahma, Varuna, Ganesha, Rudra, Kubera, Vishvakarma, Mitra...' -- Rudra is named twice (yoga 13 Vyaghata and yoga 20 Shiva); the Shiva-Yoga at index 20 derives its name from this lordship.
Bhavishya Purana — Uttara-parva, Chaturthi-vrata-kalpa (Angaraka-chaturthi-vrata-varnana), Chaturthi-vrata chapter (DLI Hindi ed., around lines 70101-70150)Krishna-Yudhishthira samvada on Chaturthi vrata including Angaraka Chaturthi.
Muhurta Chintamani — Shubhashubha Prakarana, varjya vara-nakshatra-tithi combinations, verses 20-21 (Pyarelal Mishra ed., lines 791-823)Classical text: Panchami-tithi + Hasta-nakshatra + Sunday = sarvakarya-varjya. Modern observance reads Hasta-Panchami as auspicious for Saraswati/skills — disagreement noted; classical source dominates per BPHS-first policy.
Lists 28 anandadi yogas: 'siddhi' named explicitly as one yielding karya-siddhi by its own name (siddha-yoga is the 21st nitya-yoga).
Narada Purana — Purvabhaga, Anandadi-yoga section, Anandadi 28-yoga list (sankshipta ed., around lines 42101-42150)Siddhi yoga #19 in Anandadi enumeration; 'svanama-phaladayaka' — gives fruit per its name.
BPHS — Panchanga-sadhana / Karana-prakarana, standard BPHS section on the 11 karanas (Bava-Balava-Kaulava ... Naga-Kimstughna)BPHS lists the chara-karanas (Bava through Vishti) as repeated 8 times across the 30 tithi-halves; Bava is the first and most auspicious.
Verses 28-29 enumerate the full vara-nakshatra table (Sun: Hasta/Mula/Uttaraphalguni/Uttarashadha/Uttarabhadrapada/Pushya/Ashvini; Moon: Shravana/Rohini/Mrigashira/Pushya/Anuradha; Mars: Ashvini/Uttarabhadrapada/Krittika/Ashlesha; etc.) -- matches our table exactly.
, verse 57 (Pyarelal Mishra Hindi ed., lines 2174-2196) — Sadhya not in the tyajya-list 'व्यतिपातवैधृति... परिघव्यावातगण्डयोग ... विष्टि ...'
Sadhya is conspicuously absent from the canonical 6-ninda-yoga list (vyatipata, vaidhriti, parigha, vyaghata, ganda, vajra), placing it among shubha-yogas — 'achievable goals' interpretation follows the literal 'sadhya' (to be accomplished).
, Shashthi-stuti section (devi identified as Kartikeya-pranapriya)
Verses 28-29 enumerate the full vara-nakshatra table (Sun: Hasta/Mula/Uttaraphalguni/Uttarashadha/Uttarabhadrapada/Pushya/Ashvini; Moon: Shravana/Rohini/Mrigashira/Pushya/Anuradha; Mars: Ashvini/Uttarabhadrapada/Krittika/Ashlesha; etc.) -- matches our table exactly.
, full chapters
Both adhyayas prescribe Saptami-tithi as the supreme day for Surya worship using the twelve-name list (Bhanu/Arka/Ravi/Brahma/Surya/Shakra/Hari/Shiva/Shriman/Vibhavasu/Tvashta/Varuna).
Bhavishya Purana — Brahma Parva, Saptami-kalpa (Akshyanga Saptami adhyaya 111), opening versesBhavishya Purana's Saptami-kalpa is the standard nibandha source for Bhanu/Ravi-Saptami; Sunday + Saptami amplifies it.
Muhurta Chintamani — Shubhashubha-prakarana, shantika-paushtika muhurta, verses 33-34Tuesday and Ashtami excluded from shantika muhurtas — the combination is reserved for ugra-devata worship.
Devi Bhagavata — Tantra-khanda, vrata enumeration, verses 37-40 (Bhaumavara + Pradosha vrata set)Devi explicitly names Bhaumavara-vrata in her vrata list.
Brahma listed at position 25 of the Anandadi yogas; each yoga is said to give 'svanama-sadrsha phala', so Brahma yoga gives creative / spiritual / Brahma-loka phala.
Shiva Purana — Kotirudra-samhita, Tandi Sahasranama prelude, verses 47-48Tandi (a brahma-yogi) is named as the composer of the Shiva Sahasranama in brahma-yoga — establishes the spiritual-creative significance of the yoga.
Narada Purana
— Purvabhaga, Ashtami-vrata enumeration
, Month-wise Ashtami vratas (sankshipta ed., around lines 67901-67950)
Devi Bhagavata — Skandha 3, Navaratri-vidhi (importance of Ashtami), Ashtami pujan prescription (Vol. 1 Gita Press ed., around lines 45751-45800)If unable to do full nine-day Navaratri, Ashtami tithi must be observed; references Daksha-yajna context.
BPHS — Panchanga-sadhana / Karana-prakarana, standard BPHS section on the 11 karanas (Bava-Balava-Kaulava ... Naga-Kimstughna)BPHS lists the chara-karanas (Bava through Vishti) as repeated 8 times across the 30 tithi-halves; Bava is the first and most auspicious.
Twelve-month Navami-vrata catalogue — every Navami is sacred to Durga/Chandika/Kumari in some form.
Devi Bhagavata — Tritiya-skandha (Sharad/Vasanta Navaratri narrative), Tritiya-skandha, Sudarshana-Subahu Navaratri narrative (Gita Press Vol.1, around lines 44951-45000) — 'नवरात्रेषु सर्वेषु ... अर्चनं हवनं यागं देव्या'Each Navami caps the Navaratri sequence; the day is fixed for Devi-arcana, havana, yaga.
Narada Purana — Purvabhaga, Jyotish-prakarana (ninda-yoga enumeration), ninda-yoga section (Sankshipta ed., lines 41901-41950) — 'वैधृति और व्यतीपात ये दोनों महापात हैं, इन दोनोंको शुभ कार्योमें सदा त्याग देना चाहिये'Classes vaidhriti+vyatipata as the two great mahapatas; recommends pitru-karma instead during these.
, verses 212-3, 213-4 (Sankshipta ed., lines 41901-41950) — Vishkambha listed as first of 27 yogas; later ninda-yoga group enumerates vishkambha among tyajya-portions
Vishkambha is the 1st nitya-yoga (svami: Yama); first 3 ghatikas to be avoided in all auspicious work.
(2)
Narada Purana — Purvabhaga, Ekadashi-vrata section, Ekadashi-vrata-mahatmya (sankshipta ed., text around lines 14901-14950)Detailed rules on dashami-viddha vs dvadashi-viddha Ekadashi, fasting and parana.
Brahma Vaivarta Purana — Krishna-janma-khanda, Ekadashi-vrata prescription, Ekadashi-upavasa section (sankshipta ed., text around lines 71651-71700)All Vaishnavas, yatis, widows, brahmacharis are to fast on every Ekadashi.
Matsya Purana — Surya-vamsha-varnana (origin of Vishti/Bhadra), Vishti as Chhaya's daughter (Gita Press ed., around lines 5851-5900)Vishti (Bhadra) — bhayankara-rupavali tritiya kanya — is established as kala-karana-svarupa, the personification of the inauspicious karana.
Phaladeepika — Santanachinta-prakarana (use of Vishti-karana in muhurta), verse 15 (Hindi-Alt ed., around lines 9801-9850)Phaladeepika explicitly names Vishti-karana as varjya for shubha-karya and for santana-prashna; classical avoidance rule.
Narada Purana — Purvabhaga, Karana-jnana-vidhi (11 karanas including Vishti), around verses 124-125 (sankshipta ed., around lines 34051-34100)Lists the 7 chara + 4 sthira karanas including Vishti (#7) — formula to determine karana from tithi-number.
— Sankranti-prakaranam
, verses 3, 7-8 (sthira-rashi sankranti category; snana and dana prescription)
Muhurta Chintamani — Samskara-prakarana (Pradosha-lakshana), verse 55 (Pyarelal Mishra Hindi ed., lines 3616-3650) — 'अर्कतर्कत्रितिथिषु प्रदोषः स्यात्'Defines pradosha-kala as the half-prahar around sunset on Trayodashi, Chaturdashi, Pratipad and other listed tithis.
Skanda Purana — Pradosha-vrata-mahatmya (Chandrasena and Shrikara legend), section on Pradosha-shivapujana (Sankshipta ed., lines 88951-89000)Anjananandana Hanuman teaches the gopa Shrikara the discipline of Pradosha Shiva worship.
Padma Purana — Patala-khanda, Rohini-Chandra-Shayana vrata, opening of Chandra-vrata sectionMonday-Purnima yoga explicitly identified as supreme trigger for the Rohini-Chandra-Shayana vrata; Shravana-Purnima inherits the lunar-Vishnu significance.
Parashara Smriti — Acharakanda, Upakarma-prakarana, Shravani / Hasta-paksha sectionShravana-Purnima fixed for Upakarma by Gobhila and Gargya; combined with Monday this is an exceptional Vishnu / Vedic-renewal pairing.
, full chapter (Vamana-utpatti and Bali-bandhana narrative)
Colophon: 'iti shri-matsye mahapurane vamana-pradurbhave vamanotpatti-nama panchachatvarinshad-adhika-dvishatatamo adhyayah'. Vamana-Bali boon narrative (Bali's annual return to visit subjects) is the puranic substrate for Thiruvonam.
Hindupedia — Festivals/Onam, opening section (Thiruvonam observance)Thiruvonam is the principal day of the ten-day Kerala harvest festival on Shravana-nakshatra in Chingam-masa (Sun in Simha). Onasadya, pookalam, and Vallam Kali documented in Hindupedia.
Bhavishya Purana's Raksha-bandhana-vidhi gives the canonical Shravana-purnima rakhi-tying mantra ('Yena baddho Balī rājā...') and shows brahmana-yajamana raksha-sutra prescription.
Narada Purana — Purvabhaga, Purnima-vrata-prakarana, opening section (masa-wise Purnima vratas)Sanatana-narada vada on Purnima vratas through the year.
Matsya Purana — Parva-sandhi and Purnima-tithi prakarana, section on pakshanta-sandhi and pournamasika
Matsya Purana — Surya-vamsha-varnana (origin of Vishti/Bhadra), Vishti as Chhaya's daughter (Gita Press ed., around lines 5851-5900)Vishti (Bhadra) — bhayankara-rupavali tritiya kanya — is established as kala-karana-svarupa, the personification of the inauspicious karana.
Phaladeepika — Santanachinta-prakarana (use of Vishti-karana in muhurta), verse 15 (Hindi-Alt ed., around lines 9801-9850)Phaladeepika explicitly names Vishti-karana as varjya for shubha-karya and for santana-prashna; classical avoidance rule.
Narada Purana — Purvabhaga, Karana-jnana-vidhi (11 karanas including Vishti), around verses 124-125 (sankshipta ed., around lines 34051-34100)Lists the 7 chara + 4 sthira karanas including Vishti (#7) — formula to determine karana from tithi-number.
Matsya Purana — Surya-vamsha-varnana (origin of Vishti/Bhadra), Vishti as Chhaya's daughter (Gita Press ed., around lines 5851-5900)Vishti (Bhadra) — bhayankara-rupavali tritiya kanya — is established as kala-karana-svarupa, the personification of the inauspicious karana.
Phaladeepika — Santanachinta-prakarana (use of Vishti-karana in muhurta), verse 15 (Hindi-Alt ed., around lines 9801-9850)Phaladeepika explicitly names Vishti-karana as varjya for shubha-karya and for santana-prashna; classical avoidance rule.
Narada Purana — Purvabhaga, Karana-jnana-vidhi (11 karanas including Vishti), around verses 124-125 (sankshipta ed., around lines 34051-34100)Lists the 7 chara + 4 sthira karanas including Vishti (#7) — formula to determine karana from tithi-number.
Narada Purana — Purvabhaga, Chaturthi-vrata section, Sankashta-vrata description (Sankshipta ed., lines 66301-66400) — 'माघ कृष्णा चतुर्थीको संकष्टव्रत बतलाया जाता है'Names Magha-krishna Chaturthi 'Sankashta-vrata'; prescribes upavasa, moonrise arghya to Ganesha/Chandra, gives the arghya mantra and phala.
Skanda Purana — Ganesha-Chaturthi-vrata-mahatmya, Chaturthi-vrata enumeration (Sankshipta ed., Sankashta-chaturthi reference) — moonrise-worship prescriptionAligns with the krishna-paksha chaturthi observance for relief from sankata (calamity).
Bhavishya Purana — Uttara-parva, Chaturthi-vrata-kalpa (Angaraka-chaturthi-vrata-varnana), Chaturthi-vrata chapter (DLI Hindi ed., around lines 70101-70150)Krishna-Yudhishthira samvada on Chaturthi vrata including Angaraka Chaturthi.
, Shashthi-stuti section (devi identified as Kartikeya-pranapriya)
Both adhyayas prescribe Saptami-tithi as the supreme day for Surya worship using the twelve-name list (Bhanu/Arka/Ravi/Brahma/Surya/Shakra/Hari/Shiva/Shriman/Vibhavasu/Tvashta/Varuna).
Bhavishya Purana — Brahma Parva, Saptami-kalpa (Akshyanga Saptami adhyaya 111), opening versesBhavishya Purana's Saptami-kalpa is the standard nibandha source for Bhanu/Ravi-Saptami; Sunday + Saptami amplifies it.
Matsya Purana — Surya-vamsha-varnana (origin of Vishti/Bhadra), Vishti as Chhaya's daughter (Gita Press ed., around lines 5851-5900)Vishti (Bhadra) — bhayankara-rupavali tritiya kanya — is established as kala-karana-svarupa, the personification of the inauspicious karana.
Phaladeepika — Santanachinta-prakarana (use of Vishti-karana in muhurta), verse 15 (Hindi-Alt ed., around lines 9801-9850)Phaladeepika explicitly names Vishti-karana as varjya for shubha-karya and for santana-prashna; classical avoidance rule.
Narada Purana — Purvabhaga, Karana-jnana-vidhi (11 karanas including Vishti), around verses 124-125 (sankshipta ed., around lines 34051-34100)Lists the 7 chara + 4 sthira karanas including Vishti (#7) — formula to determine karana from tithi-number.
Narada Purana
— Purvabhaga, Ashtami-vrata enumeration
, Month-wise Ashtami vratas (sankshipta ed., around lines 67901-67950)
Devi Bhagavata — Skandha 3, Navaratri-vidhi (importance of Ashtami), Ashtami pujan prescription (Vol. 1 Gita Press ed., around lines 45751-45800)If unable to do full nine-day Navaratri, Ashtami tithi must be observed; references Daksha-yajna context.
Narada Purana — Uttarabhaga, Ekadashi-vrata-mahatmya (Rukmangada-Mohini samvada), Rukmangada vrata-pratijna (Sankshipta ed., lines 76451-76550) — 'एकादशीके दिन भोजन कैसे करूँगा ... मधुसूदनके पुण्यमय दिवस एकादशीको अन्नका सेवन नहीं करूँगा'King Rukmangada's vow never to take food on Ekadashi establishes the canonical fasting rule; Thursday (Guru/Vishnu's vara) intensifies the merit.
Brahma Vaivarta Purana — Krishna-janma-khanda (Ekadashi-vrata prescription), Dharmaraja-Vasundhara samvada (Gita Press ed., lines 27701-27750) — Vishnu-bhakti centrality of EkadashiIdentifies Vishnu-seva as the supreme dharma; Ekadashi to Thursday (Vishnu/Guru) doubly auspicious for the vrata.
(2)
Narada Purana — Purvabhaga, Ekadashi-vrata section, Ekadashi-vrata-mahatmya (sankshipta ed., text around lines 14901-14950)Detailed rules on dashami-viddha vs dvadashi-viddha Ekadashi, fasting and parana.
Brahma Vaivarta Purana — Krishna-janma-khanda, Ekadashi-vrata prescription, Ekadashi-upavasa section (sankshipta ed., text around lines 71651-71700)All Vaishnavas, yatis, widows, brahmacharis are to fast on every Ekadashi.
BPHS — Panchanga-sadhana / Karana-prakarana, standard BPHS section on the 11 karanas (Bava-Balava-Kaulava ... Naga-Kimstughna)BPHS lists the chara-karanas (Bava through Vishti) as repeated 8 times across the 30 tithi-halves; Bava is the first and most auspicious.
Parashara Smriti — Madhaviya-vritti, Dana-kala-nirupana, Section on vyatipata as inauspicious yoga / sankrama (Islampurkar 1894 ed., around lines 40233-40259)Mahavyatipata defined; cited alongside ayana and vishuva as auspicious-dana times despite the yoga itself being inauspicious for new beginnings.
Skanda Purana — Maheshwara Khanda (gopa-balaka pradosha narrative), around shloka cluster cited at p.~889 of Gita Press Sankshipt edition (shanivara-pradosha worship)
(2)
Muhurta Chintamani — Samskara-prakarana (Pradosha-lakshana), verse 55 (Pyarelal Mishra Hindi ed., lines 3616-3650) — 'अर्कतर्कत्रितिथिषु प्रदोषः स्यात्'Defines pradosha-kala as the half-prahar around sunset on Trayodashi, Chaturdashi, Pratipad and other listed tithis.
Skanda Purana — Pradosha-vrata-mahatmya (Chandrasena and Shrikara legend), section on Pradosha-shivapujana (Sankshipta ed., lines 88951-89000)Anjananandana Hanuman teaches the gopa Shrikara the discipline of Pradosha Shiva worship.
