According to Hinduism, Āratī is meant to be performed at sunrise and sunset. At sunrise the Raja-Tama predominant atmosphere present throughout the night is destroyed and the Absolute fire element frequencies of Deities arrive in the Universe. Hence, Āratī is to be offered at sunrise to welcome them. The 'tārak Chaitanya' (saviour form of Chaitanya) transmitted during the arrival of the frequencies of Deities at sunrise is to be welcomed by the worshipper through the medium of the Āratī (Harathi or Aarathi), whereas at sunset, the Āratī is performed to destroy the Raja-Tama frequencies and to invoke the 'mārak Chaitanya' (destroyer form of Chaitanya) of the Deities. That is why Āratī should be performed twice, at sunrise and sunset.
What is the science in performing Āratī (Harathi or Aarathi) at sunset?
At sunset the proportion of the Absolute fire element in the Sun's rays starts reducing and the predominance of the Raja-Tama particles in the atmosphere increases. The generation of Raja-Tama frequencies also increases. Taking advantage of this situation, the negative energies increase their movement in the environment. To prevent distress from such a predominately Raja-Tama environment, it is essential to evoke the Deities through the frequencies of sound emitted through the Āratī and bring these frequencies into the orbit of the Universe. As a result the proportion of the frequencies of Deities enriched within the environment increases and the proportion of distressing vibrations decreases. This creates a protective armour around the devotee's body. (Divine knowledge received through the medium of Mrs Anjali Gadgil, 5th June 2005, 6.33 p.m.)
(Ref: Sanatan's Publication - 'How to Offer an Āratī ')
