Aum Gam Ganapataye Namah
this mantra should be chanted calmly.
from Lok Kalyan Setu (Aug'2006)

This year Ganesh-Chaturthi falls on the 27th of August, 2006. It is extremely harmful to look at the Moon on Ganesh-Chaturthi. Therefore be very careful not to look at the moon on that night.
If one happens to look at the Moon on the night of Ganesh-Chaturthi, then no matter how innocent one is, one will definitely be defamed.