Shraddhas are a
unique sort of memorial ceremonies for the departed.
A parvana shraddha may be conducted at many times during
the year, such as the new moon, but it is most usually performed during the
Fortnight of the Fathers (Pitrpaksha), which occurs during the lunar month of
Bhadrapada during the waning moon.
Unlike an ekoddishta shraddha, which summons a specific
departed person, the parvana shraddha invokes the paternal father, grandpa, and
great-grandfather first, followed by the same ancestors on the mother's side.
Although the father's ancestors are the principal receivers,
the procedure is done to bestow benefits on all of these ancestors.
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