Tide clock This is often complicated because the lead or lag varies during the course of the lunar month, as the lunar and solar tides fall into and out of synchronization. The lunar tide and solar tide are synchronized (ebb and flow at the same time) near the full moon and the new moon. The two tides are unsynchronized near the first and last quarter moon (or "half moon"). Also, in addition to the relative position of the moon and the elliptical pattern of the sun, the tide can be affected to some degree by wind and atmospheric pressure. All of these
Ecclesiastical full moon with the dates of astronomical opposition, referred to a day beginning at midnight at 0 degrees longitude, to within a day or so. However, the astronomical opposition happens at a single moment for the entire Earth: The hour and day at which the opposition is measured as having taken place will vary with longitude. In the ecclesiastical calendar, the 14th day of the lunar month, reckoned in local time, is considered the day of the full moon at each longitude. Schematic lunar calendars can and do get out of step with the moon. A useful way of checking their performance