- 3383 - JAMES WEBB - telescope compared to Hubble? The “James Webb Space Telescope” is currently poised to launch December 24, 2021, and become the most powerful telescope in space. But how will its photos compare to Hubble's?
---------------- 3383 - JAMES WEBB - telescope compared to Hubble?
- The Hubble Space Telescope launched into low Earth orbit in April 1990. Over the three decades since, the famous observatory has expanded our view of the cosmos and held our attention with the stunning images it collects. What once was a faint and mysterious abyss became a detailed and colorful universe, and we could see stars and galaxies as they'd never been seen before.
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- The James Webb Space Telescope, which is scheduled to launch on December 24, 2021, will do things differently. With its giant gold mirror and infrared light observation tools, Webb is designed to "see" objects 10 to 100 times fainter than what Hubble can see.
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- Hubble's science instruments are still going strong, and the two big scopes are set to observe together although far apart from one another in space. Hubble in low Earth orbit, but Webb will travel out much farther, to a gravitationally stable spot 930,000 miles from Earth known as the Sun-Earth “Lagrange point” 2 (L2).
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- Webb's images will also be fundamentally different, because it's different wavelengths. While Hubble observes light at primarily optical and ultraviolet wavelengths, Webb is designed to detect primarily “infrared light“.
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- The stars themselves fade away they get fainter and fainter when you go to a longer wavelength, but interstellar clouds go brighter and brighter and brighter. Some gas and dust features become a bit wispy as you start to edge into the infrared light part of the spectrum.
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- If you just go a little bit further out into infrared the dust itself lights up in thermal light. You get a nebula that shines.
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- Hubble can see light that in a wavelength range from about 200 nanometers (nm) to 2.4 microns, whereas Webb's range will go from about 600 nm to 28 microns. Even though Webb primarily observes infrared light, it will still be able to see the red/orange portion of the visible light spectrum. The gold coating of its mirrors absorbs blue light from the visible spectrum, but it does reflect yellow and red visible light that will be detected.
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- Although it is not its primary observation function, Hubble has the ability to observe some infrared as well, so this type of observation is not a complete departure. In fact, in 2013, the Hubble team released a stunning infrared image of the Horsehead Nebula.
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- Hubble has provided the world with stunning images for decades and has similar sharpness to Webb. Webb's angular resolution, or sharpness of vision, will be the same as Hubble's. Webb images will appear just as sharp as Hubble's do. Webb's resolution would allow it to see the details of an object the size of a U.S. penny 24 miles away.
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- Webb has a much larger mirror, 21.3 feet wide, compared to 7.8 feet, cutting-edge detectors and is designed to see deeper into the infrared spectrum than Hubble.
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- By observing in infrared, Webb will allow scientists to see much farther out into the universe. Its larger mirror also gives it more surface area to collect light, enabling the scope to peer even farther out into space, which essentially allows scientists to look "back in time," at the universe billions of years in the past.
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- Webb was designed to be able to "see" the first stars and galaxies that ever formed in the early universe. It can detect objects 10 billion times fainter than the faintest stars visible with no telescope, or 10 to 100 times fainter than what Hubble can observe.
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- Webb is equipped with four scientific instruments to help it make its observations:
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------------------- Near Infrared Camera (NIRCam),
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------------------- Near-Infrared Spectrograph (NIRSpec),
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------------------- Mid-Infrared Instrument (MIRI)
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------------------- Fine Guidance Sensor/Near Infrared Imager and Slitless Spectrograph (FGS-NIRISS).
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- With these tools, Webb can do what we call imaging spectroscopy, where it can take an image, but it will take a spectrum and every pixel of the image as well. In imaging spectroscopy, there is information on the spectrum of wavelengths present in each tiny piece of the image. This can help clue scientists in as to what elements or chemicals might have created that spectrum.
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- Webb's unique suite of imaging tools will allow it to do all sorts of other scientific work, such as observing exoplanets transiting in front of stars or determining the composition of a cloud in a star-forming region. Studies may look for ice, water and complex organics in the atmospheres of exoplanets.
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- Webb is still on track to launch on Dec. 24, 2021, atop an Arianespace Ariane 5 rocket from Europe's Spaceport in Kourou, French Guiana.
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- December 23, 2021 JAMES WEBB - telescope compared to Hubble? 3383
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--------------------- --- Thursday, December 23, 2021 ---------------------------
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