Islamic liturgy, mandatory ritual prayer in Islam (salat) is performed five times a day at dawn, noon, afternoon, sunset, and night. It requires ritual cleanliness, and is preceded by ablutions. The salat is also preceded by a call to prayer announced by a muezzin. It consists of the repetition of prayer cycles (raka) each composed of a sequence of postures and recitation of Qur'anic passages and special formulas. The person performing the salat is positioned facing Mecca. While salat can be performed individually or communally, the Friday noon prayer is necessarily communal, and is therefore performed at the mosque. This prayer is preceded by a sermon. This, and other special prayers (such as id prayers, which celebrate the two major Islamic feasts corresponding to the end of the fast of the month of Ramadan and to the hajj; tarawih, a prayer performed during Ramadan; and funeral, eclipse, rain, and fear prayers). The core Islamic liturgy is simple and uniform. This core is however supplemented by other forms of prayers, both individual and communal, that provide a wide spectrum of practice. The personal prayer is often accompanied by the recitation of customary texts, such as Dua Kumayl. These texts show considerable variation across the Islamic world. Prayers other than salat are often ritualized, notably within those Sufi orders that incorporate music, formalized dancing, and rythmical chanting of the names of God.