sahasra purna chandrodayam In India it is custom to celebrate the completion of 1000th full moon day of the person from his birth as sahasra purna chandrodayam. This is usually celebrated in 82-83 years. So, the occasion is the person has seen 1000 full moons in his Life. In Sanskrit sahasra means 1000 and purna means full and chandrodyam means dawn of moon. Similar kind of celebration for elderly persons is Shashti poorthi or Sashtiaapdapoorthi