I have looked at Dr. Brian Marsden's Catalog of Cometary Orbits and the only comets listed were in 684, 760 and 770 BC. Chinese observations include comets during the years 710-713 AD, 730 AD and 739 AD, and Halley's Comet appeared in 690 and 763 AD. My references show no 'historical' comets in 729 AD. This doesn't mean there weren't any, only that the books I consulted do not list any.