Day-yogas — weekday and nakshatra combinations
Day-yogas are a second, older layer of yogas from the muhurta tradition, unrelated to the panchanga's yoga limb or to chart combination yogas: they name specific pairings of weekday and nakshatra, or weekday and tithi, that the classical literature singles out as strongly auspicious or strongly adverse.
Pairing the day against the nakshatra or the tithi
Each day-yoga is defined by a small table: for a given weekday, the classical source lists one or more nakshatras (or, for one yoga, one within-paksha tithi) that combine with that weekday to form the named yoga. Checking whether a day-yoga is active is a matter of taking the day's actual weekday and the Moon's actual nakshatra (or the day's tithi) and seeing whether that pair appears in the table for the yoga in question.
Because the tables are keyed on weekday, a day-yoga can only recur when its weekday comes back around, and even then only on the days within that weekday when the Moon also happens to be passing through the paired nakshatra.
Sarvartha Siddhi — favourable for all undertakings
Sarvartha Siddhi ("accomplishing all purposes") is the most broadly auspicious of the day-yogas: each weekday is paired with a short list of nakshatras, and the classical reading holds that the combination favours undertakings generally, without being tied to one particular kind of activity the way a purpose profile is.
Cross-checked against
Muhurta Chintamani (Rama Daivajna) 28-29 and the printed सर्वार्थसिद्धियोगचक्र table, 1939 ed. p.15, read from the page image. Transcribed table matched the pre-existing engine table EXACTLY across all seven varas — no correction needed.
Amrita Siddhi
Amrita Siddhi is a narrower cousin of Sarvartha Siddhi: rather than a short list, each weekday is paired with exactly one nakshatra, and the classical sources treat the combination as similarly auspicious when it occurs.
Cross-checked against
Kalaprakasika (N.P. Subramania Iyer) p.206, closing "Siddha yoga" paragraph: "The following combinations produce a fortunate Yoga:— ... asterism Hastha and Sunday; Mrigasirsha and Monday; Aswini and Tuesday; Anuradha and Wednesday; Pushya and Thursday; Revathi and Friday; Rohini and Saturday." Read from the p.206 page image. All SEVEN vara x nakshatra pairs match this table EXACTLY. Independently corroborated a second time within the same book: KP ch.XXXV (pp.199-201) lists each of the seven in the auspicious Amirtha-or-Siddha set for its own vara. Muhurta Chintamani still does not table this discretely — its Amrita sits inside the 28-yoga vara x nakshatra system (MC 24-26, pp.12-14), a different framework.
Ravi yoga
Ravi yoga works differently from the other day-yogas: instead of pairing a weekday with a nakshatra from a table, it counts the distance, in nakshatras, from the Sun's nakshatra to the Moon's nakshatra on a given day. When that inclusive count lands on one of a specific set of values, the yoga is read as present and favourable — a mechanism closer to tara bala's counting logic than to the weekday-lookup tables the other day-yogas use.
Not yet cross-checked
This reading is applied and scored, but its table has not been matched line by line against a printed source. Muhurta Chintamani (standard published definition; pending edition/verse verification) NOT corroborated by Muhurta Chintamani: MC frames Amrita, and the adverse yogas generally, inside its 28-yoga vara x nakshatra system (MC 24-26, pp.12-14) — a DIFFERENT framework from the discrete Amrita-Siddhi / Ravi / Dagdha pairings tabled here, so it cannot confirm or refute these rows.
Mrityu yoga
Mrityu ("death") yoga is built the same way as Sarvartha Siddhi and Amrita Siddhi — a weekday paired with a listed nakshatra — but the classical reading is adverse rather than auspicious, and it is weighted as one of the more severe day-yoga penalties.
Cross-checked against
Muhurta Chintamani (Rama Daivajna) 30, 1939 ed. pp.15-16, read from the page images. Verse 30 gives four consecutive nakshatras from a per-vara base as Utpata / Mrityu / Kana / Siddhi; Mrityu is the SECOND. The p.16 prose spells out Budha/Guru/Shukra/Shani explicitly (Ashwini, Mrigashira, Ashlesha, Hasta). Matched the pre-existing table EXACTLY for all seven varas.
Dagdha ("burnt") tithi
Dagdha is the one day-yoga built on tithi rather than nakshatra: each weekday is paired with one within-paksha tithi number (that is, a position from one to fifteen within whichever fortnight is current), and the classical reading treats that combination as adverse, in the same spirit as Mrityu.
Not yet cross-checked
This reading is applied and scored, but its table has not been matched line by line against a printed source. Kalaprakasika (N.P. Subramania Iyer) p.206, "Dhugtha yoga" (the press's transliteration of Dagdha): "This is also an unfortunate Yoga formed by the combination of Thithi and day:—Wednesday and Dhwithiyai; Thursday and Shashti; Friday and Ashtami; Saturday and Navami; Sunday and Full-Moon or Dhwadhasi; Monday and Ekadhasi; Tuesday and Panchami." Read from the p.206 page image, not OCR. SIX of the seven rows match this table exactly; Wednesday CONFLICTS (KP gives Dvitiya, this table gives Tritiya) and Sunday is a superset in KP (Purnima as well as Dvadashi). Muhurta Chintamani has no discrete vara x tithi dagdha table — its adverse yogas live in the 28-yoga vara x nakshatra system (MC 24-26, pp.12-14), a different framework. Stays verified:false on the strength of the one disputed cell.