Hindu and other Eastern astrological traditions make use of sets of either 27 or 28 Lunar Mansions to divide up the zodiacal stars.
Its accepted that the one set of 27 Mansions or Hindu Nakshatrs are linked to the 27.3 days of the Moon's modern modern sidereal cycle. But the origin of the alternative set of 28 LMs is one of the underlying mysteries of numerous astrological traditions which now have a Worldwide following.
The 28 Hindu Nakshatra or 28 Chinese Hsiu simply came from the 360 day year used in India in Vedic times. This archaic calendar described by Roman and Greek writers such as Hesiod, was also in use in ancient China,, Japan, Korea, Arabia, Palestine, Persia, Assyria, Babylon and Sir Lanka. It was in use in Egypt until the reign of Amenhotep I, who made calendar reforms to take account of changes to the sidereal and synodic cycles of the Moon. This was at the time or a few years before the eruption of There in 1628 BC.
William Whiston, a contemporary of Newton and Halley, in support for his argument that there had been a 360 day year in early Biblical times noted that a 360 day year was used for the calendars in the New World. In "Worlds in Collision" Velikovsky devoted a whole chapter to the 360 day year, but only briefly mentions Hindu Nakshatra.
Modern astronomers are adamant that the 360 day year could not have been based on accurate astral observation,s but it has already been noted that the star maps showing the divisions of the Nakshatras could only be based on careful observation of the movement of the Moon against the background of the zodiacal stars.
A Hindu table expresses the total extent of the 28 Nakshatras as 831 muhurts, which would have been exactly 27.7 days. This confirms that the Moon's sidereal cycle for a 360 day Vedic year must have been used to generate the older 28 mansion Nakshatra sets.