According to the Hindu Vedic calendar, there are 30 lunar also known as tithi or phases. Amavasya is also one of the lunar which usually falls in the middle of the month.
It occurs when the Moon (Chandra) lies within twelve degrees of the angular distance between the Sun (Surya) and the Moon before the conjunction. The day is also known as the dark moon tithi.
The Amavasya, that is, the no moon day observed in the month of Vaishakha is known as Vaishakha Amavasya. The day is not believed to be auspicious as it is the day when negative energy, negative powers and evils spirits are very strong.
On this day, no auspicious work is performed and any work, prayer or travel done on the day of Amavasya is not expected to be a success. So the Hindus generally avoid any inauguration, any ceremony or travelling.
Vaishakha Amavasya is on Saturday, 4th of May 2019.
Vaishakha month is the 2nd month as per the Hindu calendar and the months of April and May in Gregorian calendar. Vaishakha Amavasya comes right after the Chaitra Amavasya. This day is considered to be auspicious for performing the tantric pooja, Kaal Sarp dosh pooja, black magic and shraadh ceremonies.