Sighting of the moon

Hazrat Abu Hurairah  (may Allah be pleased with him) says that the
 Holy Prophet (peace be upon him) said: “Start fasting on seeing the
 new moon and stop fasting also on observing the same. If you are
 unable to spot it due to the sky being cloudy then treat the month of
 Sha’aban as of 30 days.” (Bukhari &Muslim)

Hazrat Talha bin Ubaidullah (may Allah be pleased with him ) says that
 on sighting the new moon, the Holy Prophet  (peace be upon him ) used
 to pray thus:

Allahuma Ahillahu Alaina Bil Am’ne  Wal Imane Was-salamate Wal Islam
  Rabbi Wa Rabukkallah . Hilal Rush ‘din Wa Khair 

 “O Allah, do let the appearance of this moon be a forerunner of peace,
 faith, safety, and Islam for us. (O moon) mine and your Lord is Allah.

May this be a moon of (right) guidance and Virtue.”