Countdown to Webb’s first images


Commissioning of the James Webb Space Telescope is nearing completion. The sunscreen, mirrors, instruments and all other components of Webb are almost ready to begin the long-awaited scientific activities of the Observatory! This historic moment will finally kick off on July 12, with the unveiling of Webb’s first high-resolution color images.

To see the broadcast of Webb’s first live images, go to NASA Live on July 12 at 10:30 am (CEST).

Artist’s impression of the James Webb Space Telescope in space. (Credit: STScI)

Since its launch on Christmas morning 2021, the James Webb Space Telescope has completed several crucial milestones that have prepared it for scientific observations. The telescope was first fully deployed by moving to its final destination in orbit around the Lagrange 2 point 1.5 million miles from Earth, then its mirror segments were aligned and it was cooled to its optimum operating temperature, which is only 40 degrees above absolute zero (or -233 degrees Centigrade). Now Webb just needs to make sure his scientific instruments are working properly.

The four scientific instruments of the Webb telescope are housed in the Integrated Science Instrument Module behind its main mirror. (Credit: NASA / Chris Gunn)

The Webb telescope has four scientific instruments in addition to its guiding camera, the Fine Guidance Sensor (FGS), provided by the Canadian Space Agency (CSA). The four scientific instruments are capable of using a variety of tools, methods and techniques to study the Universe in different ways.

  • the NIR Cam (Near-InfraRed Camera) is a near-infrared camera provided by the University of Arizona that will be Webb’s primary imaging tool. He can also perform coronagraphy, a technique to block light from a very bright central object to better see the less bright objects around it. It also acts as the telescope’s wavefront sensor, allowing the 18 segments of the Webb mirror to function as one large mirror.
  • the NIRSpec (Near-InfraRed Spectrograph) is a near-infrared spectrograph that breaks down light into its individual colors or wavelengths. It is provided by the European Space Agency (ESA) with contributions from NASA. It can collect the spectra of many objects at once, including through a method called integral field spectroscopy, which simultaneously records spatial and spectral information.
  • the MIRI (Mid-InfraRed Instrument), provided by the European Space Agency, is the only mid-infrared instrument aboard Webb. With this ability, he will be able to see the glow of cosmic dust and gas directly, instead of seeing through it as is the case with instruments that operate in the near infrared. Since it observes longer wavelengths, it must be cooled to an even lower temperature: only 7 degrees above absolute zero.
  • the NIRISTE (Near-InfraRed Imager and Slitless Spectrograph) is the Canadian scientific instrument. It can simultaneously collect images and spectra of thousands of near-infrared celestial objects. It can also use a technique called interferometry to acquire images of objects very close to each other. To learn about the four modes of NIRISS, check out this post on the CSA blog or this post on the NASA blog.

There are a total of 17 distinct modalities that need to be verified before the four Webb tools are considered science-ready. (Credit: NASA / ESA / CSA)

Before Webb is ready for scientific activities, a total of 17 distinct modalities in the four tools must be verified. The Canadian team, including our director René Doyon and several other iREx researchers, were delighted to announce that the NIRISS instrument was the first to be ready for science on June 27th! The MIRI team then announced that their tool also completed its full modality verification on June 30th. NIRCam and NIRSpec will follow in the coming days.

Hubble’s Ultra Deep Field, an image that required 800 exposures during Hubble’s 400 orbits around the Earth in 2003 and 2004, shows nearly 10,000 galaxies, including some of the furthest known galaxies at the time. (Credit: NASA / ESA / S. Beckwith (STScI) / Team HUDF)

To celebrate the transition from the end of the Webb telescope’s six-month commissioning period to the start of its scientific observations, NASA, ESA, CSA and all other mission partners will transmit the first images to telescope colors! During a press conference on June 29, it was revealed that this long-awaited first broadcast will include the spectrum of an exoplanet’s atmosphere and the deepest image ever taken of the Universe, even deeper than the Hubble telescope’s ultra-deep field.

We invite the world to share this incredible moment with the Webb team and astronomers from around the planet:

  • Check the countdown : How many minutes are left before the inauguration? The official countdown is at
  • Listen live the first images of the presentation event : See the images revealed in real time and hear the experts talk about these exciting results on NASA TV at 10:30 am (EST) July 12:
  • Look at the first pictures : Are you only interested in great pictures? You can find the first spectra and images and at the following address:
  • Follow the agencies on social networks : Follow the project on Twitter, Facebook and Instagram with @asc_csa, @NASA and @NASAWebb using #UnfoldTheUniverse!
  • Download images : High resolution downloads and additional content will be available at:
  • ask your questions : On July 13, ask your questions about these first images and spectra using #UnfoldtheUniverse and you may receive the answer on NASA Science Live at:


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