Final answer:
The moon must be at its maximum declination angle for the alignment necessary for a lunar eclipse, which occurs when the Earth is between the Sun and the moon during a full moon. This angle is a result of the 5-degree inclination of the moon's orbit relative to the ecliptic. The lunar cycle and its phases also affect ocean tides and the visibility of surface features on the moon.
Step-by-step explanation:
The necessity for the moon to be at its maximum declination angle is closely linked to the occurrences of lunar eclipses. The moon's orbit is inclined at about 5 degrees to the ecliptic, the apparent path of the Sun across the sky. Lunar eclipses occur when the Earth is directly between the Sun and the moon, forming a straight line. For this alignment, the moon must be near one of the two points where its orbit intersects the ecliptic plane, also known as nodes, at the time of a full moon. When at maximum declination, the moon is at its furthest point from the equator within this inclined orbit and is more likely to align perfectly with the Earth and the Sun to create an eclipse.
The moon's phases, including the full moon event, stem from the changing angle of its illumination by the Sun. A full moon happens when the moon is opposite the Sun in the sky, fully illuminated, and visible all night. The lunar cycle and its phases, influenced in part by this declination, contribute to ocean tides and affect how we observe the moon's surface through binoculars or telescopes. When observing at angles other than full phase, features on the moon's surface are more pronounced due to the shadows cast by oblique sunlight.