|| Om Gurave Namah ||
I was just reading the Vedanga Jyotisham of Lagadha translated by Dr. Suresh Chandra Mishra. I would recommend this book to any one interested in Vedanga Jyotish.The basics of Panchaga comes from Vedanga Jyotish.
Somakara is the one of earliest known commentator of Vedanga Jyotish, In more recent time another well known commentator is Balgangadar Lokmanya Tilak.
For those who are interested in reading/Researching on Vedanga Jyotish (of Lagadha), below are some good links,
There are two Vedanga Jyotish text available in Veda's, One in Rig Veda and another in Yajur Veda. Both are from Lagadha.
"There are in all 36 Verses in RVJ (Rig, Rik or Arch Veda Jyotish) and 43 in YVJ (Yajur Veda JYotish) out of which 19 verses have the same meaning. We have 6 verses in RVJ which are not included in YVJ."
1) Vedanga Jyotisham by Dr. Suresh Chandra Mishra.
2) Vedāṅga Jyotiṣa of Lagadha in Its R̥k and Yajus Recensions By Lagadha,
T. S.Kuppanna Sastry, K.Venkateswara Sarma
Link : http://books.google.co.in/books?id=K84MAAAAIAAJ
3)Vedā̄ṅgajyotiṣam: Yajurvedināṃ paramparayā''gatam vistr̥tasaṃskr̥tabhūmikayā
On Vedic astrology and astronomy; critical edited text with Hindi and Sanskrit commentaries.
By Lagadha, Ācārya-Śivarāja Kauṇḍinnyāyana, SammodavardhanaKauṇḍinnyāyana, Somākara
1) Title:The distinctive features of Rik-Jyotisha
Authors:Holay, P. V.
Publication:Bulletin of the Astronomical Society of India, vol. 26, p.51 (BASI Homepage)
Link : http://adsabs.harvard.edu/abs/1998BASI...26...51H
2) Vedanga Jyotisha and Vedic Calendar
By Pramodavardhana Kaundinnyayana
Yajusha Vedanga Jyotisha consists of 44 stanzas. Eastern and western scholars suppose that the treatise was written some 3400 years ago. The treatise was in vogue in Vedic tradition until recently. But some astronomers are ill informed that Vedanga Jyotish is primitive and unscientific. But the fact is just the opposite. In Vedic tradition, Vedanga Jyotisha of Lagadha is the most ancient scripture for the determination of 'Kala' (time). A few commentaries are now available on it. One of them written by Somakara is known to be quite ancient. Shankar Balakrishna Dikshit said that Somakara's Bhasya was not mentioned in any other works in Sanskrit lierature4. But it was mentioned in Vishnubhatta's Purusharthachintamani. In the modern age different scholars have tried to analyse the Vedanga Jyotisha. A. Weber, G. Thibout, Janardan Balaji Modak, Shankar Balakrishna Dikshit, Chhotelal Barhaspatya, Sudhakar Dwivedi, Bal Gangadhar Tilak, R. Shamashastri and others
presented their notes on Vedanga Jyotisha. Very recently H. M. Yajnik and T.S.K. Shastri are also known to have edited the Vedanga Jyotisha.