W. M. Keck Observatory

Big tools look at the stars.

These tools sit on a high hill in Hawaii. There are two large tools there. They have big mirrors to catch light.

One mirror is made of many small parts. These parts work as one big piece. This helps the mirror stay the right shape.

Computers help move the small mirror parts. This happens very fast. It keeps the view clear.

These tools help us see far away. They help us learn about space. It is fun to look up!

The W. M. Keck Observatory sits high on a mountain.

It is on Mauna Kea in Hawaii. There are two large telescopes there. They sit at 4,145 meters high. These tools help us see far into space.

Building these telescopes was a big task. One man named Howard Keck gave $70 million. This helped build the first telescope. The first one began science work in 1993. The second one began in 1996.

The mirrors on these telescopes are very special. A single large mirror would be too heavy. It might sag and change shape. Instead, each mirror uses 36 small parts. These parts are called segments. Each segment is a hexagon shape. They work together as one big mirror.

A system called active optics keeps the mirror steady. This system uses sensors and small motors. The motors move the parts twice every second. This keeps the mirror shape very precise. It also helps the telescope stay strong. Each telescope weighs more than 300 tons.

Many tools help the telescopes work. These tools can take pictures or study light. One tool is named HIRES. It helps us find planets outside our solar system.

The W. M. Keck Observatory is a special place for looking at the stars.

It sits very high up on Mauna Kea in Hawaii. The telescopes are at an elevation of 4,145 meters. This high spot helps scientists see much clearer into space. There are two main telescopes at this site. They are used to study the universe in amazing ways. These tools help us learn about the history of our cosmos.

Building these telescopes required a very clever way to make mirrors.

A single piece of glass that large would be too heavy. It would sag and lose its shape as it moved. To fix this, designers used active optics. This means the mirror is made of 36 hexagonal segments. Each segment is 1.8 meters wide and weighs half a ton. A computer system moves these parts twice every second. This keeps the mirror shape very steady and precise.

Designing this technology took many years of hard work.

In 1977, Terry Mast and Jerry Nelson first proposed the idea. They wanted to build a very large telescope on the ground. In 1985, Howard B. Keck gave $70 million to help. This money started the building of the first telescope. The Keck I telescope began its science work in May 1993. The second telescope, Keck II, began its work in 1996.

There are many important facts about these huge machines.

Each telescope weighs more than 300 tons in total. They use an altazimuth mount to stay strong and stiff. This mount uses about 270 tons of steel. The mirrors were made by Itek Optical Systems in Massachusetts. They used special glass from a German company called Schott AG. The telescopes have a diameter of about 10 meters. They are some of the most important tools in astronomy.

Scientists use many different tools called instruments to study light. Some instruments take pictures of very distant galaxies. Others, like HIRES, break light into different colors. This helps scientists find planets outside our own Solar System. Another tool named MOSFIRE can see near-infrared light. It uses a special unit that can be changed by remote control. These tools allow us to see things that are very faint. They turn the light from space into new discoveries.

The W. M. Keck Observatory is a world-class astronomical facility located in Hawaii.

It sits near the summit of Mauna Kea at an elevation of 4,145 meters. This high altitude is vital for clear views of the cosmos. The observatory consists of two massive optical reflecting telescopes. When they were finished in 1993 and 1996, they were the largest of their kind on Earth. Today, they remain among the most powerful tools for studying the universe.

To build such large telescopes, engineers had to solve a major problem with mirror weight. A single piece of glass large enough for these telescopes would be too heavy. It would sag microscopically under its own weight as it turned. This sagging would cause aberrations, or distortions, in the optical path. To solve this, designers used a technique called active optics. Instead of one solid piece, each primary mirror is made of 36 hexagonal segments. Each segment is 1.8 meters wide and weighs half a ton. These segments work together to act as one single, contiguous mirror.

The active optics system keeps the mirror surface incredibly precise. Each of the 36 segments sits on a rigid support structure. Under every segment, there are three actuators, which are small parts that move to adjust position. A computer-controlled system of sensors and actuators monitors the mirror constantly. The system adjusts each segment's position twice every second. This rapid movement counters the effects of gravity and environmental changes. Because of this, the mirror maintains a surface shape accuracy of just four nanometers.

The history of the Keck Observatory began with a vision in 1977. Designers Terry Mast and Jerry Nelson proposed the concept for a large, ground-based telescope. In 1985, Howard B. Keck provided $70 million to fund the first telescope. Construction of Keck I began in September 1985, and it saw first light in 1990. Keck II followed after further donations allowed construction to start in 1991. Keck I began science observations in May 1993, while Keck II began in April 1996. Jerry Nelson, the project scientist, helped pioneer the multi-mirror technology used here.

Each telescope is a massive feat of engineering and heavy materials. The mirrors were crafted in Massachusetts by Itek Optical Systems. They used Zerodur glass-ceramic, a material provided by the German company Schott AG. Each telescope uses an altazimuth mount to stay strong and stiff. This design requires less steel than older equatorial designs. For the Keck telescopes, the mount uses about 270 tons of steel. This brings the total weight of each telescope to more than 300 tons. Each primary mirror has an equivalent diameter of 10 meters.

Astronomers use a wide variety of instruments to study different types of light. Some tools, like the Low Resolution Imaging Spectrograph (LRIS), capture images of the most distant objects. Other tools, called spectrometers, break light into colors to study its composition. The High Resolution Echelle Spectrometer (HIRES) is one of the most complex. It can measure the intensity of thousands of color channels. HIRES has helped detect planets outside our Solar System. It can even provide evidence for theories regarding the Big Bang.

Other specialized instruments allow for even deeper exploration. MOSFIRE is a multi-object spectrometer designed for near-infrared light. It features a cryogenic Configurable Slit Unit that can be adjusted remotely in under six minutes. The Keck Planet Finder (KPF) is a newer instrument that arrived in 2022. It is designed to find exoplanets using the radial velocity method. The observatory is managed by the California Association for Research in Astronomy. This non-profit includes partners like Caltech, the University of California, and NASA. These institutions work together to share the incredible discoveries made at Mauna Kea.