NASA announced recently that the James Webb Space Telescope (JWST) is aligned with all four of its science instruments. Remember, the telescope is a 21-foot diameter mirror composed of 18 separate hexagonal mirrors in three sections, that had to be folded for its ride into space. These sections, along with their respective mirrors then had to unfold and come together in the proper configuration for alignment.
And boy, they did it! NASA is so thrilled it sent out over the wire comparative photos using the JWST vs its predecessor, the retired Spitzer Infrared Telescope. What a difference a bigger mirror and more sensitive instruments make! See the included images. Reminds me of when I donned my first pair of glasses. I couldn’t believe the world was that sharp.
The image in question is a close-up of a star-forming region in the Large Magellanic Cloud, a satellite galaxy of our Milky Way. Once you’ve seen our Milky Way galaxy, joined by the Large and Small Magellanic Clouds you will be spoiled. I highly recommend it, but you do need to travel to the southern hemisphere to get a good look. While you’re at it, visit Australia, New Zealand, anywhere well south of the equator.
JWST’s instruments are specialized for infrared astronomy, as their names imply.
The Near-Infrared Camera (NIRCam) “sees” wavelengths of 0.6 to 5 microns – wavelengths as long as a bacterium. These are the wavelengths produced by forming stars and galaxies, cold small objects in our Kuiper Belt, even planets orbiting other stars.
The Near-Infrared Spectrograph (NIRSpec) also examines wavelengths in the 0.6 to 5 micron range. Instead of getting direct images of the objects however, it will disperse the light and analyze the resultant spectrum. This will help identify the chemistry, temperature, and mass of the objects in study.
The Fine Guidance Sensor/Near-Infrared Imager and Slitless Spectrometer (FGS/NIRISS) is a mouthful! It’s a combo unit working in the 0.8 – 5 micron wavelength range. The FGS will provide exceptional pointing and guiding while the NIRISS will operate in three wavelength modes, looking for exoplanets, and studying exoplanet atmospheres.
The Mid-Infrared Instrument (MIRI) will utilize both a camera and spectrometer to examine the 5-25 micron wavelength range. This is the realm of highly red-shifted galaxies, so distant and speeding away so fast their light is not visible with the Hubble Space Telescope. JWST will see them, analyze them, and provide data for discoveries we cannot anticipate. MIRI will also search for faint, distant comets, and Kuiper Belt Objects. MIRI will be NASA’s ‘Jack-in-the-Box” – full of surprises.
Next step is to calibrate each instrument, so JWST is on schedule for commissioning in about two months. Yes!
What’s in the Sky?
May 25-27; an hour before sunrise; east: We have a rare event unfolding in the pre-dawn hours. Venus, Jupiter, Mars, and Saturn are strung out low in the east-southeastern sky. Joining them for these days is a waxing crescent Moon!