Jyotiṣa was never meant for everyone and the ancients followed an oral tradition to a greater extent which meant that the knowledge wasn’t passed to anyone who is unfit to pursue the science. I should clarify here that it doesn’t have anything to do the with caste system or other discriminatory factors. It is just anyone who follows the rules laid out by the ancient Indian rishis and scientists for an astrologer to be able to serve the society in the best possible manner. However, in the post modern society, because of the advancements in technology, access to anything is available to anyone. This is both boon and bane in any field. Although this worked in growing the art of Jyotiṣa, it has led to distortion of Jyotiṣa and today we see a huge amount of contamination and pollution that has reduced the dignity of the science which was once practiced by the greatest rishis of the sacred vedic land.
Unfortunately, modern-day Sanskritists have started translating the verses that they think are related to astrology from Śrīmad-Bhāgavatam, only to arrive at utterly incorrect conclusions which is portraying the 2000 year old uninterrupted tradition (only post common era - who knows how long before that) in a bad light.
The Śrīmad-Bhāgavatam Verse
Śrīmad-Bhāgavatam is the source of every astrologer who uses the tropical zodiac for Jyotiṣa claims as a primary and the only source to claim that Indian astrology was done by the tropical zodiac by the rishis and sages. Unfortunately, anyone who claims to have translated and promotes this view is only grossly incorrect in their understanding of Sanskrit and also astronomy.
यन्मध्यगतो भगवांस्तपतपतिस्तपन आतपेन त्रिलोकीं प्रतपत्यवभासयत्यात्मभासा स एष उदगयनदक्षिणायनवैषुवतसंज्ञाभिर्मान्द्यशैघ्य्रसमानाभिर्गतिभिरारोहणावरोहणसमानस्थानेषु यथासवनमभिपद्यमानो मकरादिषु राशिष्वहोरात्राणि दीर्घह्रस्वसमानानि विधत्ते ॥ ३ ॥
yan-madhya-gato bhagavāṁs tapatāṁ patis tapana ātapena tri-lokīṁ pratapaty avabhāsayaty ātma-bhāsā sa eṣa udagayana-dakṣiṇāyana-vaiṣuvata-saṁjñābhir māndya-śaighrya-samānābhir gatibhir ārohaṇāvarohaṇa-samāna-sthāneṣu yathā-savanam abhipadyamāno makarādiṣu rāśiṣv aho-rātrāṇi dīrgha-hrasva-samānāni vidhatte.
Translation by Dr. Martin Gansten
'In the midst of which the Lord Sun, chief of heaters, by its heat heats up the three worlds and illuminates them by its own light. Passing through its ascending, descending and middling locations according to the seasons, in the signs beginning with Capricorn, by its slow, fast and middling motions known as the northern course, the southern course and the equinoctial, it makes days and nights long, short and middling.'
यदा मेषतुलयोर्वर्तते तदाहोरात्राणि समानानि भवन्ति यदा वृषभादिषु पञ्चसु च राशिषु चरति तदाहान्येव वर्धन्ते ह्रसति च मासि मास्येकैका घटिका रात्रिषु ॥ ४ ॥
yadā meṣa-tulayor vartate tadāho-rātrāṇi samānāni bhavanti yadā vṛṣabhādiṣu pañcasu ca rāśiṣu carati tadāhāny eva vardhante hrasati ca māsi māsy ekaikā ghaṭikā rātriṣu.
'When it moves in Aries and Libra, then days and nights become equal; and when it goes through the five signs beginning with Taurus, then days increase and one ghaṭikā [= 24 minutes] is lost from the nights every month.'
Through these verses, we can surely understand that the zodiac is defined tropically but there is no mention of using the tropical zodiac for horoscopic astrology. Each and every Sanskrit astrological text from the classical era of vedic tradition explicitly mentions the usage of the sidereal zodiac for horoscopic astrology, i.e the first point of Aries is tied to a specific Nakṣatram called Aśvini.
Brihajjatakam by Varāhamihira : Ch 1, Verse 3
The twelve signs of the zodiac, commencing with the first point of Aries and of (the asterism of) Aśvini and consisting each of nine stellar quarters and forming a circle, are respectively the head, face, breast, heart, belly, navel, abdomen, genital organ, two thighs, two knees, two ankles and the two feet of Kalapurusha.
Surya Siddhanta: Ch 1, Verse 27
तेषां तु परिवर्तेन पौष्णान्ते भगणास्मृतः।।
One which moves swiftly passes through them in a short time; one which moves slowly, in a long time. By their movement, the revolution is accounted complete at the end of asterism Revatī.
Page: 19, Surya Siddhanta, Translated by E.Burgees.
One more claim presented by the astrologers who use the Tropical zodiac to do Jyotiṣa is that the most ancient vedic texts such as the Yajur Veda and Atharvana Veda mentions Kṛttikā as the first Nakṣatram. This claim is justified by E.Burgees in his own commentary and this doesn't seem to be quoted at all but this chapter requires more attention of all the enthusiasts.
In the most ancient recorded lists of the Hindu asterisms (in the texts of the Black Yajur-Veda and of the Atharva-Veda), Kṛttikā, now the third appears as first. The time when the beginning of that asterism coincided with the vernal equinox would be nearly two thousand years earlier than that given above for the coincidence with it of the first point of Aśvini.
Page: 22, Surya Siddhanta, Translated by E.Burgees.
The Chapter 8, The Asterism of Surya Siddhanta provides more subtle clarifications to the sidereal origins of the zodiac in the Indian tradition. Astrologer Partho Banerjee has written a detailed article quoting all the classical texts on the sidereal origins of the Indian astrological tradition.
I am not saying using the tropical zodiac is wrong. I am not saying using the tropical zodiac to do Jyotiṣa is wrong.I am just saying that the understanding of the tradition is wrong. I am saying that there is absolutely zero evidence as of today to prove that Indian astrology should be done using the tropical zodiac. If one is particular about following the tradition, only the sidereal zodiac to do Jyotiṣa is correct! However, astrologers are free to use their preferred zodiac but distortion is unethical.