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English: The Moon is an enduring source of inspiration. She has witnessed the appearance of life on our planet, her light has brightened the darkest nights thus driving evolution and her changing phases have challenged human minds to pose the first scientific questions. The reason is that the presence of the Moon in the sky is at the same time reassuring and puzzling. Lunar motion is at the basis of calendars; the Saros cycle (11 years and 10 or 11 days depending on the number of leap years within) allowed even the ancient Chaldeans to predict a complex phenomenon such as the eclipses; explaining the link between the Moon and the ocean tides has been a major success for the theory of gravitation. Yet throughout the XIXth century, computing accurate lunar ephemeris was a challenging task, to the point that a genius like Isaac Newton has been reported saying that the Lunar Problem caused him so may headaches that he would think of it no more.

More recently, studying the orbital paths to reach the Moon has led the astronautical sciences to discover novel spaceways for solar system exploration as well as unveiling the connection with chaotic behaviour in dynamical systems, linking up with the seminal work of Henry Poincaré. Nevertheless, it took more than 50 years after the first human landing on our satellite to achieve the technology (e.g. propulsion systems, energy production, in-situ resources exploitation) to get back to the Moon, this time to stay. For Celestial Mechanics the Moon orbits dangerously close to the gravitational boundary between the gravitational attraction of the Earth and of the Sun and therefore it represents a stiff three-body-problem, defying pertrbation theories. This is why the celebrated scottish astronomer Archie Roy (co-author of the “Mirror Theorem” for findin preriodic orbits) used to say that his job was rather of a “Celestial Plumber”, in charge of the dirty job of disentangling orbits.

This “unfitered” image of the Moon stands for what a Celestial Plumber has to deal with: it has been obtained by putting a camera directly on the focus (no eyepiece) of a dirty small reflector telescope thus catching the beauty, the fascination, the complexity and the imperfections surrounding the Moon.

English: The celebrated Scottish astronomer and celestial mechanic Archie Roy (co-author of the “Mirror Theorem” for finding periodic orbits) used to say that his job was rather of a “Celestial Plumber”, in charge of the dirty job of disentangling orbits. This “unfitered” image of the Moon stands for what a Celestial Plumber has to deal with: it has been obtained by putting a camera directly on the focus (no eyepiece) of a dirty small reflector telescope thus catching the beauty, the fascination, the complexity and the imperfections surrounding the Moon.