English: rising of the Pleiades as seen from Delhi, 800 BC and 2000 BC

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The green grid is in 10 degree steps. The Pleiades (M45) are shown 10 degrees above the true

horizon in both instances (the approximate altitude at which they would become visible at the time of sunset on autumnal equinox). They appear at an Azimut of some 82 degrees in 800 BC, and of some 90 degrees (due East) in 2000 BC. The Pleiades rose over the true horizon (not directly observable except at sea) due east from ca. 2980 to 2880 BC, and at about 78 degrees (East by north) in 800 BC. These facts play a certain role in archaeoastronomical estimates of the dating of the w:en:Shatapatha Brahmana, see w:en:Hindu astronomy: the SB states that the Pleiades "do not swerve from the east". If this is taken as a statement accurate to the degree, it refers to a time near 2900 BC. If the statement is taken to be accurate to 1/16 of the compass (the actual accuracy for directions of the compass demonstrable for Brahmana texts), it can apply to any time between 7000 BC and AD 1000. At the generally assumed date of the composition of the Brahmanas (roughly 800 BC), it was accurate to about 1/32 of the compass.