Should the Gayatri Mantra be chanted at dawn, dusk or mid-day? Which are the three Sandhyas or can it be chanted at any time?
Well, it’s good to chant any mantra. Not only the Gayatri, but any mantra at these three times because during the three Sandhyas, the naadis or the pathways through which the prana acts in the human body are in a very sensitive and impressionable state. So any mantra chanted during such a time, has a great influence on the Pranic energies.
But, that does not mean that Gayatri should not be or can’t be chanted at other times. I think you can chant them even during other times provided, as I said earlier, the place is clean, and you are clean.
Will the Gayatri Mantra be more effective if given by the Guru to the disciple?
Not only the Gayatri Mantra, any mantra becomes more effective, if given by the right Guru to the right disciple.
I’ll explain. By right Guru, I mean, a person who himself or herself has practiced the mantra and attained perfection in that mantra or has an experience of what comes out of chanting the particular mantra for a long period of time. If such a teacher gives the mantra to the right student–when I say the right student, I mean one who, with humility, wants to understand sincerely how to chant it–then it becomes more effective.
Not only that, when a Guru gives a mantra to a disciple–right guru to the right disciple–it’s not just the sound of the mantra that is given, but the energy of the teacher who has experienced the fulfillment of the mantra is also passed onto the disciple to some extent.