We're in for a treat next this Tuesday evening, 16 July, when we will experience a partial eclipse of the moon. A lunar eclipse occurs when the Sun, Earth and the moon line up exactly and the moon passes through the Earth's shadow.
If you were standing on the moon on Tuesday evening then you would see the Earth pass directly in front of the Sun. When it is the other way round with the moon passing in front of the Sun then we would have a solar eclipse of the Sun as we did last 2 July. During an eclipse of the Sun the moon and the Sun appear almost exactly the same size, but this is only an illusion, the Sun is 400 times bigger than the moon but by coincidence it just happens to be 400 times farther away. Because of this, the shadow cast by the moon covers only a very small part of the Earth in a band no more than about 100 miles wide, anyone standing outside of this line would only see part of the Sun covered by the moon in a partial eclipse. The eclipse of 2 July cut a swathe right across South America and Argentina and wasn't visible from Spain.
An eclipse of the moon on the other hand, can be seen by anyone who can see the moon at the time of the eclipse. The eclipse on Tuesday night will be a partial eclipse as the Earth's shadow will just clip the upper part of the moon.
To watch the eclipse, look to the south east as the moon rises at about 21.15, a few minutes later at 21.30 the first glimpse of the Earth's shadow should be seen on the left hand side of the moon. Keep watching throughout the next hour as the moon rises higher and the shadow takes a bigger grip on the moon. By about 22.30 more than half of the upper part of the moon will be in darkness. Then, slowly, the shadow will recede and by midnight it will all be over.
Make the most of this eclipse as the next lunar eclipse visible from Spain won't be until 2026. But people living along the Costa Del Sol can look forward to a total eclipse of the Sun on 2 August, 2027 when the moon's shadow will pass along the full length of southern Spain.