Complex sentence: According to Pingree, there are a number of Indian astronomical texts are dated to the sixth century CE or later with a high degree of certainty and he claims that there is substantial similarity between these and pre-Ptolomaic Greek astronomy.
Split into simpler sentences: According to Pingree, there are a number of Indian astronomical texts are dated to the sixth century CE or later with a high degree of certainty. There is substantial similarity between these and pre-Ptolomaic Greek astronomy.