"We present now the basis to our identification of the names of the nakshtras from the Rgveda in a form easier to read:
Vaishaka = Swathi to Anuradha = Vayu, Indragni, Mitra= Vrsa, Bull for Indra, e.g. RV 8.33; also Vayu is some- times identified with Indra and the two together called Indravayu, and Vayu is also associated with cow (RV 1.134)
Iyasta Anuradha to Mula = Mitra, Varuna, Pitarah. = Mithuna, Gemini, from the cosmic embrace of Mitra and Varuna
Ashada = OurvaAsada to Srona = Apaha., Visvedevaha., Vishnu
= Karka, circle or Cancer, the sign of Visnu”s chakra (e.g. RV 1.155.6)
Shravana Srona to Shatabhisaj = Vishnu, Vasavah, Indra
= Simha, Lion, after Indra as in RV 4.16.14
Bhadrapada = Shatabhisaj to UProshthapada = Indra, Aja Ekapada,
Ahirbudhnya= Kanya, Virgin, apparently from Aryaman in the opposite side of the zodiac who is the wooer of maidens, kanya (RV 5.3.2)
Asvina = UProsthapada to Asvayujau = Ahirbudhnya, Pusan, Asvayujau
= Tula, Libra, from the Asvins who denote balance of pairs (e.g. RV 2.39, 5.78, 8.35)
K ̄artika = Apabharanı to Rohini = Yama, Agni, Prajapati = Ali (Vrshchika), Scorpion, from Krttika, to cut
Margasırsa = Rohini to Ardra = Prajapati, Soma, Rudra = Dhanus., Archer, from the cosmic archer Rudra (RV 2.33, 5.42, 10.125)
Pausha = Ardra to Pushya = Rudra, Aditi, Brhaspati = Makara, Goat, Rudra placing goat-head on Prajapati, and goat is the main animal sacrificed at the ritual of which Bruhaspati is the priest
Magha = Pushya to Magha = Bruhaspati, Sarpah. , Pitarah. = Kumbha, Water-bearer, from the water-pot offerings to the pitrus.
Phalguna = Phalgunıs to Hasta = Aryaman, Bhaga, Savitar = Mina, Fish, representing Bhaga (alluded to in RV 10.68)
Caitra = Hasta to Svati = Savitar, Indra, Vayu = Mesha, Ram, from Indra, see, e.g., RV 1.51
We observe that for most solar zodiac segments a plausible name emerges from the name of the deity. The choice of the symbols was also governed by another constraint. The Brahmana texts call the year as the sacrifice and associate different animals with it.21 the short sequence, these animals are goat, sheep, bull, horse, and man. Beginning with the goat-dragon at number 9 in the sequence starting with Vaishakha, we have sheep at 12, bull at 1, horse (also another name for the sun in India) as the sun-disk at 3, and man as archer at 8.
The kalachkra (Zodiacal signs) are most likely of Hindu origin because they conform to Vedic gods and myths.
by Subash Kak The Astronomical Code of the Ṛgveda (Third Edition)