Class of documents called ‘Purana’ are part of ‘Smriti’ literature of ancient India.
‘Smritis’ are the words and interpretation of seers. ‘Smriti’ literature expounds either ‘shastra’ (knowledge/science) and/or expounds code of conduct. Purana expounds Shastra and also outlines code of conduct. By definition, both change with change in time and also with the growth of our knowledge (and also at times reversal of growth in our knowledge and/or in our conduct). In short, they were (are) living documents that are modified and updated. New additions are also made.
For above reason, it is difficult, if not impossible, to find out precise timing of when a Purana was composed, was modified or last updated, unless of course seers of these ‘Smritis’ leave us with the clues when these documents were composed, modified or updated. In short, we are at their mercy.
Fortunately, many of these ‘Smritis’ do contain clues that can be explored to determine their timing. Do keep in mind the timing thus ascertained simply tells us that a particular smriti was either composed at that time, for the first time, or it could be simply the time when it was updated or modified.
With that preamble, let’s look at specific verses from Vishnu Purana:
We have at least two instances within Vishnu Purana, that allow us to ascertain the timing (for composition, modification or update).
विष्णु पुराण २:८:६७
शरद्वसन्तयोर्मध्ये विषुवं तु विभाव्यते
तुलामेषगते भानौ समरात्रिदिनं तु तत
Fall (Autumn) Equinox falls near Tula-Rashi (Zodiac Libra)and Spring (Vernal) equinox falls near Mesha-Rashi (Zodiac Aries)
(Voyager 4.5 Dynamic Sky Simulator by Carina Soft was employed in all simulations. Timing for the end points of the area of zodiac coinciding with the point(s) of equinoxes or solstices are reported)
Fall Equinox at Zodiac Libra (Tula)
(740 BCE – 2280 BCE)
Spring Equinox at Zodiac Aries (Mesha)
(60 BCE – 1860 BCE)
At this point all the fun begins. Someone trying to ‘prove’ recent origin for ‘Vishnu Purana’ would jump to the conclusion that it was written in 60 BCE. There will be others who will invoke error in measurements (and inability of ancient Indian astronomers to measure anything accurately, a completely false assumption that can be falsified rather easily, but that is another subject, and also subject of my two books already published) and claim whatever they want: – 1st Century CE, 4th Century CE, 5th Century CE and so on.
Not so fast……….
These are visual observations (Drik-pratyay). Thus anyone claiming a timing of Vishnu Purana (composition or update) at the extreme end of the time range will only expose their own agenda, not their commitment to the truth or rationality.
Taking into account the positions of nakshatra YogaTara corresponding to these regions of the ecliptic – Vishakha (Zubenschamali) and Bharani-Ashiwni (41 Aries and Hamal), one can say that the timing of above Vishnu Purana observation (composition or update) refers to a time sometime during 1600 BCE- 1800 BCE.
विष्णु पुराण २:८:२८-३१
अयनस्योत्तरस्यादौ मकरं याति भास्कर:
तत: कुम्भं च मीनं च राशे राश्यंतरं द्विज
त्रिष्वेतेष्वथ भुक्तेषु ततो वैषुवतीं गतिं
प्रयाति सविता कुर्वन्नहोरात्रं तत: समं
ततो रात्रि:त्क्षयं याति वर्द्धतेsनुदिनं दिनं
ततश्च मिथुनस्यान्ते परांकाष्ठामुपागत:
राशिं कर्कटकं प्राप्य कुरुते दक्षिणायनं
Winter solstice falls near Makar-Rashi (Zodiac Capricorn) and Summer Solstice falls near Karka-Rashi(Zodiac Cancer)
Winter solstice at Zodiac Capricorn (Makar)
(140 BCE – 2140 BCE)
Summer solstice at Zodiac Cancer (Karka)
(1460 BCE – 20 BCE)
Based on position(s) of winter and summer solstices in the context of prominent YogTara (Shravana- Altair, or Pushya-Altarf) we can say that this modification/update took place sometime during 400 BCE-200 BCE)