Can I chant the mantra in night of the hour of sun?

I am doing sun square working .each day I am reciting the sun mantra during the hour of sun. If I do any mistake to recite the sun square mantra during the hour of sun or if I forget to recite the mantra during the hour of sun, What should I do? 1)will I again start the sun square mantra in sunday? ...

I am doing sun square working .each day I am reciting the sun mantra during the hour of sun. If I do any mistake to recite the sun square mantra during the hour of sun or if I forget to recite the mantra during the hour of sun, What should I do? 1)will I again start the sun square mantra in sunday? ...