In The Secret Doctrine (1888), H. P. Blavatsky gives a figure for the age of the cosmos or solar system (SD 2.68), derived from the Tirukkanda Panchanga for Kali Yuga 4986, or 1884-1885 C.E. (SD 2.51), as 1,955,884,687 years. In a posthumously published writing fragment tentatively titled “On Cosmic Cycles, Manvantaras, and Rounds” (Blavatsky Collected Writings, vol. 13, pp. 301-306), HPB gave the same figure, obviously from the same source, but before it was adapted for 1887 by adding two years to it, 1,955,884,685. Here, rather than the age of the cosmos as a whole, or narrowed down to the age of the solar system, she applies this figure to our planetary chain (the seven rounds). Then, presumably in support of such an unusually large figure, she notes (SD 2.68 fn.) that the school of Dayanand Saraswati, the Arya Samaj, on the cover of their Arya Magazine for a similar year, gives the date, “Aryan era 1,960,852,987.”

The Tirukkanda Panchanga is a calendar or almanac, written in Tamil, and published in south India. Pañcāṅgas are published throughout India for each year. This one, HPB says, was compiled “from fragments of immensely old works attributed to the Atlantean astronomer, and found in Southern India” (SD 2.50). The “Atlantean astronomer” is Asuramaya, as she says in the section, “Two Antediluvian Astronomers” (SD 2.47-51). She takes for granted that her readers know what book Asuramaya wrote, the Sūrya-siddhānta, so does not there mention it. From a secret book ascribed to Pesh-Hun or Nārada, called the “Mirror of Futurity,” and from the work of Asuramaya (i.e., the original Sūrya-siddhānta), she tells us, come “the figures of our cycles” (SD 2.49). I say “the original Sūrya-siddhānta,” because we know that the current one is a later redaction. We know this because the old Sūrya-siddhānta as summarized in Varāha-mihira’s Pañca-siddhāntikā differs significantly from the current one.

The Sūrya-siddhānta is quite the most influential astronomical work in India, and only in the last century has it become superseded in many circles by modern astronomy. The figures given in the Tirukkanda Panchanga, like other traditional pañcāṅgas (Indian calendars, almanacs), and also the date given in the Arya Magazine, are based on the Sūrya-siddhānta. It gives (chapter 1, verse 47) 1,953,720,000 solar years since the beginning of the kalpa (eon) to the end of the last kṛta-yuga (“perfect age”), less the time taken for “creation” (sṛṣṭi, emanation or manifestation) at the beginning of the kalpa, 17,064,000 years. This figure, 1,953,720,000, is possibly original, because it is given in a verse using word-numbers. This avoids typographical errors that are frequent when using numerals. From this figure, one can calculate to the beginning of the Śaka era (78 C.E.), much used in India, as 1,955,883,179 years. Similarly, Ebenezer Burgess, in his English translation of the Sūrya-siddhānta, published in 1860, calculated to the year 1859 C.E., the figure 1,955,884,960 years (p. 173). This is only a few hundred years different from the figure given in the Tirukkanda Panchanga, and adopted by HPB in The Secret Doctrine.

Burgess noted (pp. 142, 144) that the manuscripts of the Sūrya-siddhānta used by him had somewhat different readings and arrangement than the first published Sanskrit edition (edited by Fitzedward Hall and published in 1859 in the Bibliotheca Indica series, Calcutta). This same basic text, as commented on by Raṅganātha, was also published in Calcutta in 1871, and again there in 1891 edited by Jīvānanda Vidyāsāgara. Despite the fact that at least 36 Sanskrit commentaries on the Sūrya-siddhānta are known, only two other traditional commentaries on it have been published, as far as I know. The first is that by Parameśvara. This was edited by Kripa Shankar Shukla and published in 1957 (by Lucknow University). The verse in question, 1.47, giving the figure in question, is verse 1.46 in this edition, and it has the variant reading nanda rather than randhra (both standing for “nine”). The second is that by Kamalākara Bhaṭṭa. This was edited by Śrīcandra Pāṇḍeya and published in 1991 (by Sampurnanand Sanskrit University, Varanasi). We do not have a critical edition of the Sūrya-siddhānta, in the known redaction, nor do we have any manuscript of the old version as summarized by Varāha-mihira in his Pañca-siddhāntikā.