Astronomy. Discovering the sky

Merz-Repsold refracting telescope (1882)

The Merz-Repsold telescope is linked to one of astronomy's most important moments: the birth of modern planetology.
The instrument comes from the Brera Astronomical Observatory, where it was used between the end of the 19th century and the 1960s, first at the Milan site and then at the Merate observatory.
It is Italy's largest refracting telescope and one of the biggest in the world.
Highly sought after by Giovanni Virginio Schiaparelli, who was the director of the Brera Observatory during the second half of the 19th century, the telescope was used between 1886 and 1890 to carry out in-depth studies of Mars.
This instrument was responsible for extraordinary observations of the Red Planet whose precision and detail marked a turning point in planetary studies.
These maps of Mars, drawn by Schiaparelli, reveal the presence of structures—especially the famous "canals"—that gave rise to a heated debate among scientists regarding the existence of water, vegetation, and even intelligent life on the planet. This debate went well beyond the world of science, becoming a sociological and cultural talking point. It is also inextricably linked to the birth of a new mythical creature, the Martian, and a new literary tradition that would go on to enjoy great success: science fiction.

Replicas of Galileo Galilei's telescopes (1933)

For centuries, the telescope was the astronomer's primary observation tool.
The earliest telescopes were produced at the end of the 16th century by Dutch artisans. However, they were little more than a novelty due to their poor quality. At the start of the 17th century, Galileo Galilei was the first to imagine focusing this strange apparatus, capable of bringing objects closer, on the firmament. This allowed him to study astronomical objects and phenomena more closely and in a new light. From that moment on, the telescope became a genuine scientific instrument, marking the birth of modern astronomy.
In a telescope of this type, known as a refractor, a system of lenses collects and channels light from the stars toward the observer. This allows us to see objects that are otherwise invisible to the naked eye.
Today's more modern telescopes, called reflectors, use a system of mirrors instead of lenses. Additionally, the human eye has been replaced by new electronic detectors. These ever-more sophisticated detectors allow us to observe increasingly distant objects in greater detail.

Sisson's equatorial sector (1774)

This equatorial sector is one of the oldest telescopes from the Brera Astronomical Observatory in Milan. It was used to study the planets, sunspots, and the moon. This instrument's glorious history is linked to the first scientific discovery made following the proclamation of the Kingdom of Italy. The asteroid Hesperia (the Ancient Greek name for the Italian peninsula) was discovered by Giovanni Virginio Schiaparelli on April 26, 1861. With Sisson's equatorial sector, Schiaparelli also observed the comet 1862-II, which helped him to explain the phenomenon of meteor showers.
Despite its unusual name, the instrument is actually a regular refractor telescope. Its main notable feature is its support structure, which made it particularly stable and practical to use.
Like any other telescope, the equatorial sector was used to observe and study the full range of celestial

Wooden model of the Brera Astronomical Observatory (circa 1760)

This is the original wooden model built at the end of the 18th century by Ruggero Giuseppe Boscovich to demonstrate his design for the planned Astronomical Observatory to the rector of the Jesuit College of Brera. The model reproduces the two-story observatory with its large terrace and two turrets.

Salmoiraghi refracting telescope (early 20th century)

The telescope is the astronomer's main tool. It can be used for both observations and astronomical measurements of various kinds. This model is based on the same optical principles that Galileo used in constructing his telescopes at the start of the 17th century. The objective lens is about 20 cm in diameter while its focal length is about 2 meters. Thanks to a motorized system, it can automatically follow the apparent motion of celestial objects. The telescope was acquired by the Brera Astronomical Observatory from the Milan-based company Salmoiraghi, one of the world’s most important manufacturers of scientific instruments. However, the observatory soon acquired more powerful instruments, and this telescope was thus little used.

Ramsden's mural quadrant (1789)

This quadrant is made up of a base fixed to a wall. By moving the telescope vertically, the observer can ascertain the maximum height of a star on the horizon and the moment at which this height is reached. The large scale and excellent workmanship of this instrument, produced by one of the most renowned artisans of the 18th century, allowed for great precision in terms of measurement. This quadrant was one of the first instruments to be purchased by the Brera Astronomical Observatory. For many years, it was among the most used by its astronomers.
The telescope itself is pivoted at the apex of the quadrant and can rotate freely around it, allowing it to be aimed at any star, regardless of its height on the horizon. To be used correctly, the instrument had to be positioned precisely along the local meridian (i.e. north to south) with a perfectly vertical plane.

Terrestrial and celestial globes, Venice (1688 and 1693)

Globes are tools that represent the earth and the sky. They offer a detailed picture of the knowledge of the era in which they were produced and were often made as tributes to rulers both great and small.
Celestial globes often represent the position of newly discovered comets and stars in the sky, while terrestrial globes depict new routes opened up by expeditions or the details of various conquests.
The Venetian Vincenzo Maria Coronelli was one of the greatest geographers and cartographers of the latter half of the 17th century. To create his globes, he used wooden spheres covered with plaster onto which he glued printed strips of paper that were then colored by hand.
By using printed images, he avoided having to draw directly on the globe by hand. This allowed the artist to produce many identical models in a relatively short time. Thanks to the work of cartographers like Coronelli and Moroncelli, globes became genuine works of art that were appreciated more for their beauty than for their precise representative qualities.

Akerman's armillary sphere (1766)

In astronomy, as in all sciences based on the Galilean method, the basic concepts underpinning a theory are often represented with models. This makes understanding and studying phenomena easier; in some cases, it even allows new properties to be intuited. This armillary sphere represents the universe according to the Ptolemaic view in which Earth is in the center. It is a classic representative and instructional model whose function was to offer a simplified description of the geocentric model of the universe.
The instrument is made up of four iron rings that represent four celestial meridians. There are also five rings perpendicular to the first set. These represent the equator and two celestial parallels per hemisphere. The armillary sphere can rotate around an axis that runs from one pole to the other. This axis passes through a wooden sphere in the center of the structure that represents Earth.