I’ve done a number of Videos on this subject, so I will list these first:
Here is Part 1 of a live video presentation on the topic of Sidereal and Tropical Zodiacs in Vedic Astrology:
Here is Part 2 – which includes some very helpful animations.
Here is the first class of my 102 course on the 12 signs of the zodiac, where the zodiac itself is clearly explained, and the topic of sidereal and tropical is addressed.
Here is an episode of my Q/A show that addressed the tropical basis for Elements, Modes and Rulers of the Signs:
Here is the original video I made on the subject.
Here are the key texts involved in this subject:
Chapter 14, Text 7:
bhacakra-nābhau viṣuvad dvitiyam samasūtragam
ayana dvitayan caiva catasraḥ prathitāstutāḥ
The two solstices and two equinoxes are the thread upon which the core of the zodiac exists.
tad atareṣu saṅkrānti dvitayam dvitayam punaḥ
Two borders are between each point.
bhānor marakara saṅkrānteḥ ṣaṇmāsā uttarāyaṇam
karkādestu tathavasyāt ṣaṇmāsā dakṣināyaṇam
It takes the Sun six months to reach the northern solstice after entering Capricorn; and six months to reach the southern solstice after entering Cancer.
meṣādyo dvādaśaite māsāstair eva vatsaraḥ
The twelve divisions beginning from Aries are certainly the months which constitute a year.
Division 5, Chapter 21, Text 3:
sa eṣa udagayana-dakṣiṇāyana-vaiṣuvata-saṁjñābhir māndya-śaighrya-samānābhir gatibhir
The sun moves between the northern solstice, southern solstice, and equinotical points in a cardinal, fixed, and dual manner.
ārohaṇāvarohaṇa-samāna-sthāneṣu yathā-savanam abhipadyamāno
Its rise towards the northern solstice, its fall towards the southern solstice, and its crossing the middle point can be known by observing time.
makarādiṣu rāśiṣv aho-rātrāṇi dīrgha-hrasva-samānāni vidhatte.
The days and nights grow longer and shorter, revealing which of the signs – Capricorn, etc. – the Sun is in.
yadā meṣa-tulayor vartate tadāho-rātrāṇi samānāni bhavanti
When the Sun is in Aries and Libra, the days and nights are equal.
yadā vṛṣabhādiṣu pañcasu ca rāśiṣu carati
tadāhāny eva vardhante
hrasati ca māsi māsy ekaikā ghaṭikā rātriṣu.
When the Sun is in the five signs starting from Taurus, the days grow longer and nights which grow shorter, month by month.
yadā vṛścikādiṣu pañcasu vartate
tadāho-rātrāṇi viparyayāṇi bhavanti.
When the Sun is in the five signs starting from Scorpio, the days and nights change in the opposite way.
Chapter 3, texts 2-5:
śṛṇu vipra pavakṣyāmi, bha-grahānāṁ paristhitim
Listen, scholar, I will explain the positions of the stars and planets.
ākāśe yāni dṛśyante, jyotir-bimbāny anekaśaḥ
In the sky we see many dots of light.
teṣu nakṣatra-saṁjñāni graha-saṁjñāni kānicit
Some of them are known as “stars” (nakṣatra), others as “planets” (graha).
tani nakṣatra-nāmāni sthira-sthānāni yāni vai
Those which stay fixed in their places are called “stars”.
gacchanto bhāni gṛhlanti, satataṁ ye tu te grahāḥ
But, those stars which always move, as if they had will and consciousness, are called “planets”.
Note: rāśī not mentioned. rāśī are not among the dots of light in the sky.
bha-cakrasya nagāśvy aṁśa, aśvinyādi-samāhvayāḥ
The celestial wheel has integral portions called āśvini and so on. It is like a wheel being turned by a horse.
Note: nakṣatras are integral portions of the star field, and (as “a wheel turned by a horse”) they move together as a unit in relation to something about to be mentioned:
tad dvādaśā-vibhāgas tu, tūlya meṣādi-saṁjñakāḥ
But that same space can also be divided into twelve, known as Aries (meṣa) and so on.
Note: tu – but, this indicates that the rāśī are different than what was described before (nakṣatra). tūlya – similar / like, this indicates that they are similar but not identitcal. vibhāga – differentiated division, this indicates that rāśī are distinct from the star field, unlike nakṣatra, which are aṁśa (integral, inseparable portions) of the star field.
The full text of this video is here: The 12 Signs of the Zodiac.
Comments on P.V.N. Rao:
Comments on David Frawley
I comment on all three in one post.
To my knowledge there is only one substantial rebuttal of my paper so far. Here are my responses to that rebuttal [with links to the rebuttal itself, of course].
And sometimes, I just gotta vent!