Ashad sud poonam is the auspicious Gurupoonam, one of the 3 main annual festivals of the Swaminarayan sampradaya. On this day, devotees gather and pay homage to Gurudev SwaminarayanBapa Swamibapa.

Acharya Swamishree Maharaj performs poojan to Jeevanpran Swamibapa

Jeevanpran Swamibapa explains the precise meaning of the Sanskrit word guru.

Gu means andhkaar (darkness).
Ru means prakash (light).

Thus, he who enlightens the ignorant, i.e. shines light to those in darkness, is called a Guru. It is only Lord SwaminarayanBapa Swamibapa that can enlighten us ignorant souls to the supreme bliss of eternal happiness, the endless peace of the supreme Lord. Thus our supreme Guru can only be Lord SwaminarayanBapa Swamibapa. Jeevanpran Swamibapa says, "Guru veenaa gnaan nahi." Without a Guru, knowledge cannot be attained. Lord Swaminarayan showed the importance of a Guru in ones life by taking Shree Ramanand Swami as His Guru.