What is Vaidik Astrology?

Vaidik astrology means Phalit Jyotish (predictive astrology) according to the techniques of prediction based on the position of planets vis-a-vis (so called) Niraayan Raashi and Nakshatra given in the Ved. It has got innumerable ingredients which make it a full-fledged system. Some of these are :
(1) Planetary position vis-р-vis Niraayan Raashi and Nakshatra, with several Ayanaanash like Lahiri, Raman, Fagan, Yukteswhar and so on, to name just a few of them.
(2) Planetary position vis-р-vis 27 equal Nakshatra divisions, which are quite unrelated to their namesake fixed stars
(3) It contains at least Shodash Varg, like Horaa, Dreshkaan, Navaansh, Shashtyaansh etc. etc.
(4) It contains Shad Bal with Isht Bal and Kasht Bal etc which is very difficult to compute without the help of a computer, at least an electronic calculator, if not computer
(5) It contains complete details about planetary Bindu and Rekhaa known as Ashtak Varg which is used for Gochar, which again is a part of Vaidik astrology
(6) It comprises hundreds of Yog like Nabhasa etc (there are hundreds of them and the most important ones being, Sunapha, Anapha, Durudhur, Veshi, Voshi, ubhayacharee, A-Vipareet Raaj Yog, Neechaa Bhang Raaj Yog etc, apart from the most dreaded ones like Kaal Sarp Yog (Almost all these Yog have been listed by BV Raman in his famous book Three Hundred Important Combinations)
(7) Vaidik astrology also means complete details of Dashaa Bhukti - sometimes all the 36 types of them, including Vinshottaree, Ashtotaree, Yoginee, Kaal Chakra etc as adumbrated in the Brihat Paraashara Horaa Shaastra, the bible of Vaidik astrologers, besides their Antar-Dashaa and Pratyantar and Sookshm and Praan etc. Dashaa, which are supposed to depict correct Bhavishya up to an hour.

Now coming to the point: I have not seen any birth chart of any Rishi or King etc in any of the Ved, Braahman or the Vedaang, whether on the basis of planets vis-a-vis Nakshtra, which David Frawley calls "sidereal" astrology, nor have I seen any discussion of any birth chart as per planets vis-a-vis Mesha, Vrishabh etc. Rashi. In fact, leave alone birth chart, there is no mention of Mesh, Vrishabh etc. Raashi also, much less the so called sidereal Raashi (or even tropical) nor planets like Mangal, Shani etc. in any of the Ved. Only the position of the Moon vis-a-vis various Nakshatra, i.e. Fixed stars has been mentioned. As such, there cannot be any predictive (even sidereal!) astrology without the planets like Mangal, Shani etc. vis-a-vis Nakshatra.

It also means, that since "Vaidik astrology ...is based on the fixed stars" there is no provision of any Raashi in Vaidik astrology because the Raashi used in Vaidik astrology are of equal divisions, in which are subsumed 27 equal Nakshatra divisions, which have absolutely nothing to do with their namesake Fixed stars. And because fixed stars are quite unrelated to their namesake equal Nakshatra divisions, which all the "Vaidik astrologer" of modern India are using.

What astronomical works were used by the Vaidik seers like Vishwaamitra or Vashishth or Yaagyyavalkya or Bhardawaaj or even Vaamdeva etc. for calculating Lagna, Mid-Heaven, Dashaa Bhukti, Ashtak Varg, Gochar etc. One that is available is known as Rik-Yajush (Vedaang) Jyotish of 13th-14th century BC, in which not only Mesh, Vrish etc. Raashi, but even Mangal, Shani etc. planets also are conspicuously absent. All that that work tells us is about calculating mean Tithi and lunar and solar Nakshatra apart from Madhu (Chaitra), Maadhav (Vaishaakh) etc months and Vasant etc. seasons besides Ayan and Vishuv.

It is also useful to know the names of Phalit Jyotish works as have been written by the Vaidik seers like Bharadwaaj, Vashishth, Vishwaamitra etc since Vaidik Rishi alone could have written anything about Phalit or Ganit in that hoary past. Or any of the original Vaidik astrology works, talks of any Kaal Sarp Yoga also, besides, much dreaded Saadhe Saatee. Vishwaamitra etc. must have certainly given some remedial measures of dreaded Yog, such as Kaal Sarp. Do those remedial measures talk about various kinds of gems also?

Signs (Raashi) and Nakshatra in Ved

There were no Mesh, Vrish etc Raashi in the Ved, but only Nakshatra, including Abhijit Nakshatra, so the Vaidik Raashi being Niraayan or Saayan was a meaningless question. Regarding the Vaidik Nakshatra, there is no definite starting point of any Nakshatra, much less the Nakshatra division in the Ved.

Atharv Ved, 19.17-18 gives the number of 27 Nakshatra

Different Starting Nakshatra
--Taittireeya Sanhitaa (4.4.10) and Taittireeya Braahman (1.5.1) where we have the mention of the Nakshatra starting from Krittikaa. Thus we had the custom to start from Krittikaa Nakshatra which means that the Vernal Equinox occurred when the Sun was in Krittikaa Nakshatra.
--Vedaang Jyotish and Taittireeya Sanhitaa also begins their Nakshatra series from Krittikaa but that never means that the Zodiac Belt also begins with Kriittikaa Nakshatra.
--In the same way, Tantra Literature begins its Nakshtra series from Bharanee, but that never means that Zodiac also begins with Bharanee.

Vaidik Sages fixed that Samvatsar will start from Phaalgun Poornimaa and Zodiac will start from the Ashwinee Nakshtra's initial point.
Vaidik sages are also certain that Moola is the Nakshatra which points to root of the Universe creation the galactic center.

Starting of Samvatsar
Samvatsar means the year. From when we should start our Samvatsar or year? Taittireeya Sanhitaa's (Krishn Yajur Ved) 7.4.8 says (like Gopath Braahman), that Chaitra Full Moon (Poornimaa) is the mouth of Samvatsar. This is said in the context of doing a ritual (Vishuvant). However, in next two lines of the same verse, a rider is provided for considering Chaitra Poornimaa to be mouth of Samvatsar when there are clouds are in sky during Phaalgun Poornimaa and Vishuvant rites are to begin after Phaalgun Poornimaa.