Humanity has always had a relationship with the stars.
We express this fascination for the unknown through science and art. For the ancient Greeks, they were a record of heroes and gods. For the Aztecs, they heralded the beginning and the end of days.
Monoliths like Stonehenge are theorised to be a primitive method of keeping time using celestial objects. But the first true observatories were built at Damascus and Baghdad during the 9th and 10th centuries.
Following their creation, Galileo Galilei constructed the first optical telescope in 1609. Galileo, the premier astronomer of his time, learned how to create advanced glass lenses from Finnish artisans. His telescopes opened the door for discoveries about space and revolutionised astronomy.
Today's observational telescopes have evolved beyond Galileo's model. Building off his success, different telescopes have been developed to observe the stars.
Optical telescopes enhance what is visible to the human eye. These telescopes use dioptrics — lenses and prisms — to greatly magnify distant images such as planets and stars. Many consumer telescopes operate on this principle. The largest optical telescope is at the W.M. Keck Observatory at Mauna Kea, Hawaii.
The second kind of telescope is electromagnetic telescopes. Rather than focusing on only the observable visible spectrum, these devices measure celestial objects through the part of the electromagnetic spectrum that is not visible to the naked eye.
Some of these telescopes don't look like telescopes at all. Radio telescopes use satellite dishes to observe the stars using radio waves. Infrared and x-ray telescopes can capture pictures of objects that would otherwise be invisible. Gamma-ray telescopes observe radiation from black holes and newly born galaxies.
The building is planned and constructed around the telescope, optimised for easy access. An isolated concrete pier runs from the footing to the sole plate of the telescope's pedestal. This keeps the telescope steady to minimise the risk of observational errors.
While observatories are generally designed under the same principle, it also depends on where the building will be. As various constellations are visible at different times of year, astronomers must plan their observations to ensure the proper stars will be visible from their location.
Various power sources, such as generators and backup generators, are installed to create an uninterruptible power supply. This ensures that any data collected will not be lost due to a power outage.
Modern-day observatories have two purposes. The first is to observe and learn from the stars and planets around us. The second is to share those discoveries with visitors from around the world. Here are three of the best observatories to visit in Europe.
The European Southern Observatory (ESO) is the most well-known intergovernmental astronomy program. Currently supported by 16 member states, the ESO's primary operations are in the Chilean Atacama Desert. ESO promotes many special events and has permanent exhibitions in Munich, Germany, and Santiago de Chile, Chile.
ESO operates some of the most productive telescopes in the world of astronomy. The Very Large Telescope (VLT) is one of the most powerful optical telescopes ever created. It operates four smaller telescopes with mirrors 8.2m in diameter and another four 1.8m in diameter, either simultaneously or individually. This allows the VLT to observe more details on celestial objects than conventional telescopes.
ESO operates the highly advanced Atacama Large Millimetre/submillimetre Array (ALMA) in collaboration with their international partners. ALMA is a state-of-the-art telescope that uses electromagnetic wavelengths of only a millemetre between infrared and radio waves. This makes it the only observational device to study light from the coldest objects in the universe. It is the largest ground-based astronomical project ever undertaken.
Also known as the Flamsteed House, the Royal Observatory at Greenwich is an essential site in the history of astronomy and navigation in the UK. King Charles II commissioned it in 1675, and Sir Christopher Wren was chosen to construct it. Sir Wren decided to build it on the remains of the derelict Greenwich Castle, once used by Henry VIII to house his mistresses.
John Flamsteed was appointed as the first Astronomer Royal, a position newly created by King Charles, together with the new observatory. The Astronomer Royal's mission was to serve as the observatory's director and perfect the art of navigation and astronomy. It was named Flamsteed House because the observatory also acted as a home for Flamsteed, his family and servants.
One of its most notable aspects is that the Prime Meridian — the basis of longitude measurement — passes through the observatory. That means the Royal Observatory was the basis of early experiments measuring universal time. These experiments would eventually culminate in the creation of Coordinated Universal Time (UTC).
The Royal Observatory was also responsible for creating several star charts and early experiments in positional astronomy. It continued to be used until the early 20th century when all scientific work was moved to the Royal Observatory at Herstmonceux.
The Royal Observatory at Greenwich was designated a historical site until 2018, when the state-of-the-art Annie Maunder Astrographic Telescope (AMAT) was installed. After 60 years, the Royal Observatory at Greenwich is once again a working observatory.
The leading astronomical research and observation facility in Northern Ireland, Armagh Observatory and Planetarium, was founded by Archbishop Richard Robinson in 1789. Dr. J.A Hamilton, Rector of Mullabrack, was its first director. Like the Royal Observatory at Greenwich, the Armagh Observatory has a rich history of scientific achievements.
The planetarium was opened in 1968 by then-director Eric Lindsay. It is the longest-running planetarium in the British Isles. Priding itself on being an educational facility in addition to a place of scientific research, the planetarium uses an advanced projection system to display and teach visitors about the planets, stars and other observable astronomical phenomena.
In addition to the observatory and the planetarium, Armagh also offers various exhibitions and workshops for visitors of any age.
From the Bronze Age to the present, humanity will always be fascinated by the stars and the cosmos. As we continue to develop as a species, so does our capacity to reach those distant stars one day.