A lunar month in Hindu calendar has two fortnights – Shukla Paksha and Krishna Paksha. Shukla is waxing or light phase of moon and Krishna is waning or dark phase of moon. Shukla Paksha starts after Amavasi or no moon day. Krishna Paksha starts after Full moon or Purnima. Shukla Paksha starts after new moon or Amavasya. Each paksha has 15 tithis. Each tithi has a name starting from Amavasya Pratipada Dwitiya Tritiya Chaturthi Panchami Sashti Saptami Ashtami Navami Dasami Ekadasi Dwadasi Trayodasi Chaturdasi Purnima Earlier each tithi of the Krishna Paksha and Shukla Paksha had separate names but now it has been discontinued. Krishna or Shukla is prefixed to demarcate the tithis during each fortnight. Krishna Paksha is mainly used for conducting ceremonies dedicated to dead ancestors. Shukla Paksha is mainly preferred for conducting auspicious ceremonies.