Observatory facts for kids

The Sphinx Observatory on a mountain top in the Swiss Alps at 3,571 meters (11,716 feet) high.

An observatory is a special place used to watch and study events happening on Earth, in the oceans, or in space. Scientists use observatories for many different fields. These include Astronomy (studying space), climatology (studying climate), meteorology (studying weather), geophysics (studying Earth's physical processes), oceanography (studying oceans), and volcanology (studying volcanoes). In the past, observatories could be as simple as a tool like an astronomical sextant to measure star distances. Even ancient sites like Stonehenge were used to observe astronomical events.

Astronomical Observatories

The Hubble Space Telescope orbiting Earth.

Astronomical observatories are places where scientists study objects in space. They are mainly grouped into four types:

• Space-based: These are telescopes in space.
• Airborne: These are telescopes on airplanes or balloons.
• Ground-based: These are telescopes on Earth's surface.
• Underground-based: These are special observatories built deep underground.

Ground-Based Observatories

The Atacama Large Millimeter Array in Chile, at 5,058 meters (16,594 feet) high.

The Paranal Observatory in Chile, home of the VLT, at 2,635 meters (8,645 feet) high.

The Mauna Kea Observatories in Hawaii, with some of the world's largest optical telescopes, at 4,205 meters (13,796 feet) high.

Haleakala Observatory in Maui, Hawaii, at 3,036 meters (9,961 feet) high.

Ground-based observatories are built on Earth's surface. They are used to see visible light and radio waves from space. Most optical telescopes are inside a dome or similar building. This protects the sensitive equipment from bad weather.

These domes have an opening in the roof that can be opened when observing. It closes when the telescope is not in use. Usually, the top part of the dome can spin around. This lets the telescope look at different parts of the night sky. Radio telescopes usually do not need domes.

For optical telescopes, most ground-based observatories are built far from big cities. This helps avoid light pollution, which makes it hard to see faint objects in space. The best places for modern observatories have very dark skies. They also have many clear nights each year, dry air, and are very high up.

At high elevations, Earth's atmosphere is thinner. This means there is less air movement that can blur images. This leads to better astronomical "seeing" or clearer views. Good locations for observatories include the southwestern United States, Hawaii, the Canary Islands, and the Andes mountains. Some major optical observatories are Mauna Kea Observatory in the US, Roque de los Muchachos Observatory in Spain, and Paranal Observatory in Chile.

A study in 2009 suggested that the best place for a ground-based observatory is Ridge A. This spot is in central Eastern Antarctica. It has the fewest atmospheric problems and the best visibility.

Radio Observatories

Since 1933, radio telescopes have been built to study the Universe using radio astronomy. These instruments observe the radio part of the electromagnetic spectrum. A radio observatory is a place with one or more radio telescopes and other buildings. These include control centers, visitor housing, and data centers.

Radio observatories are also built far from big cities. This is to avoid electromagnetic interference (EMI) from things like radio, TV, and radar. Unlike optical observatories, radio observatories can be placed in valleys. This helps to block even more EMI. Some important radio observatories are the Very Large Array in New Mexico, USA, Jodrell Bank in the UK, and Arecibo in Puerto Rico.

Highest Astronomical Observatories

Since the mid-1900s, many observatories have been built at very high altitudes. These are often above 4,000 to 5,000 meters (13,000 to 16,000 feet). The largest and most famous is the Mauna Kea Observatory. It is near the top of a 4,205-meter (13,796-foot) volcano in Hawaiʻi.

The Chacaltaya Astrophysical Observatory in Bolivia was the world's highest permanent observatory. It was built in the 1940s and is 5,230 meters (17,160 feet) high. In 2009, it was surpassed by the new University of Tokyo Atacama Observatory. This optical-infrared telescope is on a remote 5,640-meter (18,500-foot) mountaintop in the Atacama Desert of Chile.

Oldest Astronomical Observatories

An ancient Indian observatory at Delhi.

"El Caracol" observatory temple at Chichen Itza, Mexico.

Remains of the Maragheh observatory (under dome) in Maragheh, Iran.

Jantar Mantar in Jaipur, India.

The Estonian Tartu Observatory, a starting point of the Struve Geodetic Arc.

The 19th-century Observatory in Sydney, Australia (1872).

Ecuador's 1873-Quito Astronomical Observatory near the Equator.

The 1962-built Solar observatory on Lomnický peak in Slovakia.

Griffith Observatory in Los Angeles, California in September 2006.

Some of the oldest places used for observing the sky include:

• Stonehenge in Great Britain
• El Caracol in Mexico
• Abu Simbel in Egypt

The oldest true observatories, which were specialized research centers, include:

• 825: Al-Shammisiyyah Observatory, Baghdad, Iraq
• 1259: Maragheh Observatory, Azerbaijan, Iran
• 1420: Ulugh Beg Observatory, Samarqand, Uzbekistan
• 1667: Paris Observatory, France
• 1675: Royal Greenwich Observatory, England
• 1724: Jantar Mantar, India
• 1811: Tartu Old Observatory, Estonia
• 1873: Quito Astronomical Observatory, Ecuador

Space-Based Observatories

The Hubble Space Telescope in Earth's orbit.

Space-based observatories are telescopes or other instruments located in outer space. Many of them orbit Earth. These space telescopes can see things in wavelengths of the electromagnetic spectrum that cannot pass through Earth's atmosphere. This means they can observe things that ground-based telescopes cannot.

Earth's atmosphere blocks ultraviolet light, X-rays, and gamma rays. It also partly blocks infrared light. So, observing these parts of the spectrum is best done from above the atmosphere. Another benefit of space telescopes is that their images are very clear. They are not affected by the air movement that blurs images from ground-based telescopes.

Because of this, space telescopes like the Hubble Space Telescope can see much finer details than ground telescopes of similar size. However, space telescopes are much more expensive to build. They are also very hard to fix or maintain because they are so far away. The Hubble Space Telescope was special because it could be serviced by the Space Shuttles. Most other space telescopes cannot be repaired at all.

Airborne Observatories

SOFIA on board a Boeing 747SP.

Airborne observatories are telescopes carried by aircraft, like airplanes or balloons. They fly high above most of Earth's atmosphere. This gives them a clearer view than ground observatories. They also have an advantage over space telescopes. Their instruments can be set up, fixed, and updated much faster and cheaper.

The Kuiper Airborne Observatory and the Stratospheric Observatory for Infrared Astronomy (SOFIA) use airplanes. They observe in the infrared part of the spectrum. Infrared light is absorbed by water vapor in the atmosphere, so flying high helps. High-altitude balloons have also been used in many countries for X-ray astronomy.

Volcano Observatories

A volcano observatory is a place that watches and studies a volcano. They also do research to understand what might happen if a volcano becomes active. Some well-known ones are the Hawaiian Volcano Observatory and the Vesuvius Observatory. There are also mobile volcano observatories. The USGS has a program called VDAP (Volcano Disaster Assistance Program). They can send these mobile observatories to volcanoes when needed.

Each volcano observatory is responsible for a certain area. They are in charge of sharing forecasts about volcanic activity. They also analyze possible threats and work with local communities to prepare for volcanic eruptions.

See also