Lunar month with the Sun one or two days before that evening ("e.g.", in the Islamic calendar). In ancient Egypt the lunar month began on the day when the waning moon could no longer be seen just before sunrise. Others use calculation, of varying degrees of sophistication, "e.g.", the Hebrew calendar or the ecclesiastical lunar calendar. Yet others run from full moon to full moon. Calendars count integer days, so months may be 29 or 30 days in length, in some regular or irregular sequence. In India the month from conjunction to conjunction is divided into thirty parts known as "tithis". The
Apollo 15 operations on the Lunar surface Apollo 15 operations on the Lunar surface Apollo 15 lunar surface operations were conducted from July 30 to August 2, 1971, by Apollo 15 Commander David Scott and lunar module Pilot James Irwin, who used the first lunar rover to make three exploratory trips away from their landing site at the base of the Apennine Mountains, near Hadley Rille. They collected a total of of lunar surface material during 18½ hours outside their lunar module, "Falcon". At 104 hours, 30 minutes and 12 seconds GET the descent engine of "Falcon" ignited. Burning at about 10% for the first 26 seconds