Sources

Everything quoted on this site is listed here. Where authorities differ, this site follows Sringeri — the app already takes its pañcāṅga from Śrī Śāradā Pīṭham, and it would be incoherent for the writing around it to prefer some other reading. Variants are noted as variants.

Published by Sringeri Śāradā Pīṭham

• Sandhya Kala Mayukha — the Peetham's own sandhyā timing calculator. Source for the prātaḥ window running from 48 minutes before sunrise, the sāyaṃ window running 72 minutes after sunset, and the uttama / madhyama / adhama divisions of each.
• sringeri.net — the Peetham's main site, including the Anugraha Bhāṣaṇams.

Words of the Jagadgurus

• Jagadguru Sri Sri Sri Bharati Tirtha Mahaswamiji, on making time for the daily rite — as recorded in KCDT Sandhyavandanam Q&A, compiled by the Sandhyāvandana Abhyasana Śikṣaṇa Samiti, an affiliate of the Kalvakolanu Chitranjan Das Memorial Trust, Hyderabad; founder-president Brahmaśrī Kalvakolanu Srirāmachandra Murthy. A record of the Jagadguru's instruction, not a Peetham publication.
• Jagadguru Sri Chandrashekhara Bharati Mahaswamiji, The Sandhyā Worship — the conversation with a touring education officer, compiled by Sri R. Krishnaswamy Iyer and reproduced as chapter 8 of the Mahadevan booklet below.
• Jagadguru Sri Abhinava Vidyatirtha Mahaswamiji, two essays in Kannada on Gāyatrī Mahima and Sandhyā Mahima, translated into Tamil by Changanur Subramaniya Aiyar and published in 1999 by Śrī Śāradā Trust, Bangalore — a principal source of the Mahadevan booklet.

From other Peethams

• Pujyasri Chandrasekharendra Saraswathi Swamiji of the Kanchi Kamakoti Peetham — the cycle-pedal answer to “my life is going well without it”, quoted at Writing. The English rendering is the one that circulates widely; we have not traced it to a primary publication and say so there rather than invent a citation.

Further reading

• Vedaghosham — Trikāla Sandhyā Vandanam, an accessible overview of the rite, its three parts and the Gāyatrī counts, which puts the same generational argument in terms of an inherited store of puṇya that depletes when it is not replenished. Linked, not reproduced.

Books and compilations

• B. Mahadevan, Thoughts on Sandhya Vandanam (2014; v6, 2015) — an English booklet written for “youngsters and office goers”, drawing on the Abhinava Vidyā Tīrtha essays, the bhāṣya of Srivatsa Somadeva Sarma (Vaidika Dharma Vardhini, Chennai, 1952), the Sandhyā Vandanam Bhāṣya by “Anna” (Ramakrishna Math, Mylapore, 1956), and Saṃkṣepa Dharma Śāstra by Manjakudi Venkatarama Sastrigal (Heritage India Educational Trust, 1985).
• Sandhya Vandanam Rules — a Telugu compilation of the timing rules, with the ghaṭi division of the day, the uttama/madhyama/adhama verses, and the prāyaścitta arghya.
• Yajurveda Sandhyavandanam (English) and Sandhya_Vandanam — procedural manuals.

Verses cited

• Vyāsa Smṛti — upāste sandhivelāyāṃ niśāyāṃ divasasya vā…, on the derivation of the word sandhyā.
• Gobhila — sandhyā yena na vijñātā…, on the consequence of never learning or performing it.
• sandhyāhīno'śucir nityam anarhaḥ sarvakarmasu…, on unfitness for other rites.
• Kūrma Purāṇa — yo'nyatra kurute yatnaṃ dharmakārye dvijottamaḥ…
• Atri — sandhyā trayantu kartavyaṃ…, that all three are to be performed.
• Devī Bhāgavatam 11.16.4–5 — the grades of the prātaḥ and sāyaṃ sandhyā.
• Praśna Upaniṣad 1.3–1.5 — ādityo ha vai prāṇo rayireva candramā, cited in the Mahadevan booklet.
• Bhartṛhari, Vairāgya Śataka — ādityasya gatāgataiḥ…, on the days that shorten a life unnoticed.

A note on how these are used

No statement is attributed to a Jagadguru here unless it appears in a named written source, and those two are quoted rather than paraphrased. Where the sources disagree — as they do on how long before sunrise the morning window opens — the Peetham's published reading is the one followed and the other is recorded as a variant. Corrections are welcome at medury@gmail.com.