Panchak (Panchaka)
Panchak is the roughly five-day stretch each month when the Moon passes through Aquarius and Pisces, from mid-Dhanishta to the end of Revati. Tradition avoids a few specific activities during it.
Also known as: Panchak kaal, Dhanishta Panchak
Panchak, ‘group of five’, covers the Moon’s transit through the last five nakshatras: the second half of Dhanishta, then Shatabhisha, Purva Bhadrapada, Uttara Bhadrapada and Revati. In terms of signs, it begins when the Moon enters Aquarius and ends when it leaves Pisces, so it returns about every 27 days and lasts about four and a half days.
Five things are traditionally avoided in Panchak: travelling south, gathering wood or fuel, laying a roof, making a bed or cot, and, if a death occurs, a cremation without a prescribed extra rite. A Panchak starting on Sunday is called Roga, on Monday Raja, on Tuesday Agni, on Friday Chora and on Saturday Mrityu; Wednesday and Thursday starts are considered milder.
Panchak is not a blanket ban. Several of its nakshatras, including Uttara Bhadrapada and Revati, are classical choices for weddings and griha pravesh, and everyday life goes on as normal. It is a custom of timing a few tasks, not a period of danger.