Officially "surveying the sky"! Can "Mozi" on a 4,200-meter-high mountain help us see the universe clearly?

Today, at the Lenghu Astronomical Observatory in Qinghai, the WFST officially started astronomical survey observations and research, and successfully released images of the Andromeda Galaxy.

This is the world's only large-aperture and large-field-of-view optical time-domain survey telescope to date. It is also the telescope with the strongest optical time-domain survey capability in the northern hemisphere. It can survey the entire northern celestial sphere once every three nights and capture images of the entire northern celestial sphere, making it a true "starry sky photographer."

On September 17, the Mozi Sky Survey Telescope was officially put into use.

Image source: University of Science and Technology of China

At 10:30 a.m. on the same day, the first light photo of the Andromeda M31 galaxy, a celestial body about 2.5 million light-years away from the Earth, was sent back, drawing applause from the academicians and experts who were witnessing the first light ceremony in Lenghu. This was the "debut" of the Mozi Survey Telescope.

The picture shows the Andromeda Galaxy taken by the Mozi Survey Telescope. The Andromeda Galaxy M31 is about 2.5 million light-years away from Earth and has a diameter of about 200,000 light-years. This photo was taken by the Mozi Survey Telescope through 150 exposures of 30 seconds each, a total of 150 photos superimposed and synthesized.

Image source: Chinese Academy of Sciences

Can "Mozi" help us see the universe clearly?

The construction of the Mozi Survey Telescope began in July 2019. Unlike the Chinese Sky Eye (FAST) radio telescope, the Mozi Survey Telescope is an optical telescope that works in the visible light band.

Image source: CCTV News

The Mozi Sky Survey Telescope is named in honor of the ancient Chinese scientist Mozi, who discovered for the first time more than two thousand years ago that light travels in a straight line and conducted pinhole imaging experiments. He is known as the "world's first person in optics."

It has a large light-transmitting area, little stray light, high system detection sensitivity, and powerful sky survey capabilities. It can survey the entire northern celestial sphere once every three nights. It is the most powerful optical time-domain survey device in the northern hemisphere... The Mozi Survey Telescope has many "hard power" capabilities.

The Mozi Sky Survey Telescope consists of four major subsystems: the telescope body, the prime focus camera, the telescope dome site, and data storage and analysis. It is equipped with a 765-million-pixel large-target prime focus camera. Its core scientific goal is to search for and monitor astronomical dynamic events and conduct time-domain astronomical observation and research. It is currently the astronomical observation equipment with the strongest optical time-domain survey capability in the northern hemisphere.

This is the main structure of the Mozi Sky Survey Telescope.

Time domain astronomy is a hot research field in astronomy. This field is the key to answering important scientific questions such as the origin and evolution of stars, the nature of black holes, the physical state of neutron stars, and the origin of superheavy elements in the universe. It is reported that the Mozi Survey Telescope targets time domain astronomical events, such as supernovae, gamma-ray bursts, electromagnetic counterparts of gravitational waves, solar system bodies, and even new transient sources that have not been predicted by theory.

At the same time, Mozi will complement the Vera Rubin Observatory Large Synoptic Survey Telescope (VRO/LSST) in the southern hemisphere, which is expected to be put into operation in 2025, in terms of sky coverage, realize all-day time-domain monitoring, and promote the development of time-domain astronomy.

In recent years, news about near-Earth asteroids flying past the Earth has often attracted public attention. The survey data of the Mozi Survey Telescope can be used to monitor near-Earth objects and assist in early warning and defense. Near-Earth objects refer to solar system objects whose orbits are close to the Earth's orbit, including asteroids and comets.

According to reports, the superposition of the survey data of the Mozi Survey Telescope will provide the deepest high-precision, large-area, multi-color photometry and position star catalog in the northern celestial sphere. As the handed-down survey data, it can be used for the identification and systematic research of various celestial bodies in the universe in the next few decades. At the same time, the Mozi Survey Telescope will be oriented towards the national aerospace power strategy, carry out the search and monitoring research of near-Earth objects in the solar system, and serve the strategic needs of aerospace safety and deep space exploration.

Comprehensive sources: Xinhua News Agency, Science and Technology Daily, etc.