e the Full and New-moon
sacrifices (darsapur_n_amasa); the Season-sacrifices (_k_aturmasya),
each season consisting of four months;[133] and the Half-yearly
sacrifices, at the two solstices. There are other sacrifices
(agraya_n_a, etc.) to be performed in autumn and summer, others in
winter and spring, whenever rice and barley are ripening.[134]

The regulation of the seasons, as one of the fundamental conditions of
an incipient society, seems in fact to have been so intimately
connected with the worship of the gods, as the guardians of the
seasons and the protectors of law and order, that it is sometimes
difficult to say whether in their stated sacrifices the maintenance of
the calendar or the maintenance of the worship of the gods was more
prominent in the minds of the old Vedic priests.

The twenty-seven Nakshatras then were clearly suggested by the moon's
passage.[135] Nothing was more natural for the sake of counting days,
months, or seasons than to observe the twenty-seven places which the
moon occupied in her passage from any point of the sky back to the
same point. It was far easier than to determine the sun's position
either from day to day, or from month to month; for the stars, being
hardly visible at the actual rising and setting of the sun, the idea
of the sun's conjunction with certain stars could not suggest itself
to a listless observer. The moon, on the contrary, progressing from
night to night, and coming successively in contact with certain stars,
was like the finger of a clock, moving round a circle, and coming in
contact with one figure after another on the dial-plate of the sky.
Nor would the portion of about one third of a lunation in addition to
the twenty-seven stars from new moon to new moon, create much
confusion in the minds of the rough-and-ready reckoners of those early
times. All they were concerned with were the twenty-seven celestial
stations which, after being once traced out by the moon, were fixed,
like so many mile-stones, for determining the course of all the
celestial travellers that could be of any interest for signs and for
seasons, and for days and for years. A circle divided into
twenty-seven sections, or any twenty-seven poles planted in a circle
at equal distances round a house, would answer the purpose of a
primitive Vedic observatory. All that was wanted to be known was
between which pair of poles the moon, or afterward the sun also, was
visible at their rising or setting