On the day of the Shraddha of the father or mother, one should repeat the Gayatri mantra ten times at dusk. He should do so on the days when the study of the Veda is prohibited, and on these days it is for twenty eight times. On auspicious days, Gayatri should be repeated 1000, 500, 300 or 128 times. On Sankranti and other days, if the annual Shraddha also falls, one should first offer libation of water to the dead and then alone start performing the Shraddha.