2MASS

A big tool looked at the whole sky.

It used light we cannot see. This light helped it see through dust. The tool found many space things. It saw small stars and big galaxies. It even found a tiny galaxy nearby. It found over 300 million objects. Many people can use this data for free. It is a great way to see space.

Scientists wanted to see the whole sky. They used a project called 2MASS. This project used infrared light. This is a type of light we cannot see.

The project took place from 1997 to 2001. It used two large telescopes. One was in Arizona. The other was in Chile. These tools looked at the North and South skies.

2MASS found many things in space. It found over 300 million small objects. These include stars and small planets. It also found 1 million big objects. These are called extended sources. This group includes galaxies and nebulae.

One big goal was to find brown dwarfs. These are very low-mass stars. The project found 173 of them. It also helped find star clusters. One team even found a small galaxy. They called it the Canis Major Dwarf Galaxy. It is very close to our Milky Way. Now, anyone can look at this data online for free.

The 2MASS project was a huge look at the sky. It was an astronomical survey of the whole sky. This means scientists looked at everything above us. They used a special kind of light called infrared light. This light is different from what our eyes see. It helps us find things that are hard to spot. 2MASS helps us learn about the deep parts of space.

This project worked by using three different light bands. These bands are called J, H, and K. They use light near 2 micrometres. The team used special detectors called HgCdTe detectors. These tools helped them make a photometric survey. This is a way to measure light. Computers then looked at the data. They cataloged stars, planets, and asteroids.

This work happened between 1997 and 2001. Scientists used two different locations for the telescopes. One was at Mount Hopkins in Arizona, USA. The other was in Chile. Each place had a 1.3-meter telescope. The Arizona telescope looked at the Northern Hemisphere. The Chile telescope looked at the Southern Hemisphere. A final data release happened in 2003.

2MASS found many amazing things in space. It found over 300 million small objects. These include low-mass stars and brown dwarfs. The project found 173 brown dwarfs in total. One was named 2MASS J04414489+2326333. It also found 1 million extended sources. These are bigger things like nebulae and galaxies. In 2003, scientists found the Canis Major Dwarf Galaxy. This is a very close satellite galaxy.

This survey helps us see through dark areas. Our own galaxy, the Milky Way, can hide things. This is called the Zone of Avoidance. Infrared light lets us see through that strip. It also helps us find star clusters. Now, this data is in the public domain. Anyone can go online to see it for free. It is a gift for all of science.

The Two Micron All-Sky Survey, known as 2MASS, was a massive astronomical survey. It aimed to map the entire sky using infrared light. Infrared light has wavelengths longer than the visible light we see. This special light allows astronomers to see through cosmic dust. 2MASS was designed to find many different types of objects. It helped scientists study stars, galaxies, and even small planets.

To complete this mission, the survey used two major telescope sites. One site was the Fred Lawrence Whipple Observatory in Arizona, USA. This telescope observed the Northern Hemisphere from Mount Hopkins. The second site was the Cerro Tololo Inter-American Observatory in Chile. This telescope focused on the Southern Hemisphere. Each site used a 1.3-meter telescope to collect data. The survey took place between 1997 and 2001. The final data release for the project occurred in 2003.

The survey operated using three specific frequency bands. These bands are named J, H, and K. They focus on short-wavelength infrared light near 2 micrometres. To capture this light, the team used HgCdTe detectors. These detectors allowed for a photometric survey. A photometric survey is a way to measure the brightness of objects. This process helped create a very detailed map of the sky.

2MASS produced a massive astronomical catalog of discovered objects. The survey identified over 300 million point sources. These point sources include stars, planets, and asteroids. The team also found 1 million extended sources. These extended sources include larger things like nebulae and galaxies. These items are stored in the 2MASS Extended Source Catalog, or 2MASX. Automated computer programs were used to catalog these objects. They reached an average limiting magnitude of about 14.

One major goal was to find objects in the "Zone of Avoidance." This is a strip of the sky obscured by the Milky Way. Our own galaxy blocks much of the visible light in this area. However, infrared light can pass through this obstruction. This allows 2MASS to detect galaxies hidden behind our own galactic dust. The survey was also designed to find low-mass stars. These are the most common types of stars in our galaxy.

The survey was incredibly successful at finding rare objects. 2MASS discovered a total of 173 brown dwarfs. Brown dwarfs are objects that are larger than planets but smaller than stars. Some examples include 2MASS 0939-2448 and 2M1207. In November 2003, scientists used 2MASS data to find something huge. They discovered the Canis Major Dwarf Galaxy. At that time, it was the closest known satellite galaxy to the Milky Way.

Infrared measurements from 2MASS have also unveiled new star clusters. These clusters were previously undiscovered by other methods. The project was supported by several major organizations. These include NASA and the National Science Foundation. The University of Massachusetts Amherst and the IPAC also sponsored the work. Today, the data is in the public domain. Anyone can access these images and data online for free. This makes the discoveries available to all of science.