The phase of the moon this Monday, April 13, 2026, is waning, according to the official astronomical calendar for the period. Este stage of the lunar cycle occurs shortly after the full phase and precedes the arrival of the new moon, expected to occur in four days. The natural satellite of Terra currently shows a gradual reduction in its illuminated area visible to observers on the planet. The phenomenon is part of the lunation, which is the average time interval of 29.5 days between two consecutive new moons. Durante this process, the gravitational interaction and the relative position between the Lua, the Terra and the Sol determine the luminosity variations. The current April cycle began with the full phase on the first day of the month and will end with the rising phase.
Lunar calendar details for the month of April
Monitoring changes on the satellite allows us to identify the four main phases that make up the complete cycle. In April 2026, astronomical events were distributed to cover the entire month, starting on the 1st. The waning phase, which takes effect this Monday (13th), officially began last Friday, April 10th.
The exact dates and times of phase changes for this month are as follows:
- Full moon:day 1, at 11:11 pm
- Waning moon:10th, at 01:51 am
- New moon:17th, at 8:51 am
- Crescent moon:23rd, at 11:31 pm
The transition between each stage lasts approximately seven days, completing the orbital path around Terra. Após the end of the current waning phase, the satellite will enter the new phase, when it will be positioned between the planet and Sol.
Visual characteristics and mechanics of the waning phase
This Monday (13), Lua has a shape that resembles the letters “C” or “D”, depending on the observer’s perspective. No Hemisfério Sul, this appearance is specific due to the viewing angle in relation to sunlight. The satellite moves to the point where its face facing Terra will no longer reflect sunlight directly to the observer.
The current calculated distance between Lua and the center of Terra is 399,877.13 kilometers. Embora the distance varies slightly during the orbit, this value represents the position of the celestial body during this part of the waning phase. Visibility decreases daily until the satellite reaches the necessary alignment for the new phase next Friday.
The rotational movement of Lua occurs during the same period as its translation around Terra. For this reason, terrestrial observers can only see one of the satellite’s faces, regardless of the phase it is in. The lighting varies, but the exposed geographic surface remains constant for those observing from the ground.
Differences in observation between hemispheres
The appearance of the natural satellite changes depending on the observer’s geographic location on the Earth’s surface. No Hemisfério Sul, the curvature of illumination in the waning or waxing phase appears inverted when compared to the view of someone at Hemisfério Norte. The phenomenon is purely perspective, since the star and its orbit are the same for the entire globe.
In the waning phase, sunlight reaches the eastern half of the satellite before dawn. No Hemisfério Norte, the illuminated part refers to the letter “C”, while in Sul the visual perception changes. Essa variation is one of the fundamental points for basic navigation and for understanding agricultural and tidal calendars in different regions of the planet.
Each of the four main phases determines a specific level of visibility and brightness. In the new phase, the satellite is in the same direction as Sol and is therefore not visible at night, appearing in the sky only during the day. Já in the full phase, which opened the month of April, Lua reflects sunlight across its entire surface facing Terra, being the period of maximum luminosity.
How the lunation and orbit cycle works
The lunar cycle, also technically known as lunation, is the period necessary for Lua to return to the same phase. Este time of 29.5 days is an average and may suffer small variations due to gravitational disturbances from other celestial bodies. The Terra-Moon system maintains a dynamic where the phases are direct consequences of reflected sunlight.
- Waning:Período reduction in brightness after the full phase.
- New:Alinhamento between Sol and Lua, making the satellite invisible at night.
- Growing:Aumento Gradual of the illuminated area after the new moon.
- Full:Iluminação total visible face of the satellite.
The transition observed this Monday (13) is the final stage before the cycle “restarts” in the new phase. Durante waning, the satellite rises and sets later and later, becoming visible mainly at the end of the morning and during part of the day. The understanding of these cycles is applied in several areas, from professional astronomy to the planning of maritime and fishing activities.
