Lunar eclipse. When does the Sturgeon Moon begin, and how and where can you see it?

Following the solar eclipse in mid-August, the sky will offer a new astronomical event to mark the end of this summer. On the night of 27–28 August, a very deep partial lunar eclipse, known as the "Sturgeon Moon", will take place. The eclipse will begin at 3.23 am, when the Moon enters the Earth’s penumbra; at 4.33 am, the Moon will begin to enter the umbra, marking the start of the most interesting phase, which will reach its peak at 6.12 am, when the Moon will appear near the western horizon and the sky will begin to brighten. During the most intense phase, around 96 per cent of the lunar disc will be covered by the Earth’s shadow. It will therefore not be a total eclipse, as a small part of the surface will remain outside the Earth’s shadow cone. The distinctive name of this eclipse derives from the traditions of the Native American peoples settled in the Great Lakes region, along the present-day border between the United States and Canada. In August, sturgeon would swim upstream in large numbers, and the period was considered particularly favourable for fishing. The full moon is also known by other names linked to agricultural activities and late-summer harvests, including the Green Corn Moon, the Wheat Moon and the Blueberry Moon.

A lunar eclipse occurs when the Sun, Earth and Moon are aligned, or nearly so. The Earth lies between the Sun and the Moon and casts a cone of shadow into space, which may cover the Moon’s surface either entirely or only partially. This alignment occurs during the full moon phase, but not at every full moon, because the Moon’s orbit is tilted relative to that of the Earth. The portion immersed in the shadow does not disappear completely: some of the sunlight passes through the Earth’s atmosphere before reaching the Moon’s surface. The air scatters the blue components of the light in particular and allows the red and orange components to filter through more readily, following a mechanism similar to that which colours sunsets. The final hue can vary depending on the amount of dust and clouds present in the atmosphere: the greater the number of particles, the more intense the red may appear. This favours warm tones, ranging from copper to the deepest red, giving rise to the popular names ‘Red Moon’ or ‘Blood Moon’.

The eclipse will be visible, at least in part, across large areas of the Americas, Europe and Africa. The best conditions for observing the entire event will be in the Americas, whilst in much of Western Europe the Moon will set before the eclipse ends. In Italy, the eclipse is expected to begin at around 4.40 am, whilst the peak, as mentioned earlier, should be reached at 6.12 am, with variations depending on geographical location. The event will be particularly well-suited for viewing in the central and southern regions, whilst in the northern regions, the Moon will set shortly after the peak. This means that the final phase will not be visible: the Moon will remain low on the western horizon, whilst the brightness of dawn will gradually increase. For this reason, it will be necessary to choose a spot with an unobstructed view to the west, free from buildings, trees or hills. Weather conditions will play a decisive role: clouds, mist or obstacles along the horizon could prevent you from observing the peak phase. The penumbral phase – during which only part of the Sun’s rays is blocked by the Earth and which, in this case, will begin during the night – will, however, be barely discernible without specialised equipment. Unlike a solar eclipse, observing a lunar eclipse does not require any filters or special protection: the phenomenon can be viewed with the naked eye.