Compare JWST with the bands imaged by the earth observing Landsat satellites, which are more sensitive to visible (shorter) wavelengths, but the short wave IR only up to about 2.5 microns. The thermal IR (in a separate instrument) starts above 9 microns.https://landsat.gsfc.nasa.gov/satellites/landsat-8/

Kelsey Jordahl

@kajord

The first JWST image released was a composite of 6 different infrared bands, F090W, F150W, F200W, F277W, F356W, and F444W. I'm not sure exactly how the IR bands were mapped to RGB, but generally the longer wavelengths are red and the shorter ones are blue.

7/12/2022, 12:41:15 PM

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Kelsey Jordahl

@kajord

The wavelength bands that JWST can image range from around 500 nm to over 5 microns.

http://ircamera.as.arizona.edu/nircam/in_filters.php

7/12/2022, 12:44:14 PM

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Kelsey Jordahl

@kajord

Compare JWST with the bands imaged by the earth observing Landsat satellites, which are more sensitive to visible (shorter) wavelengths, but the short wave IR only up to about 2.5 microns. The thermal IR (in a separate instrument) starts above 9 microns.

https://landsat.gsfc.nasa.gov/satellites/landsat-8/

7/12/2022, 12:48:37 PM

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Kelsey Jordahl

@kajord

Landsat (and other earth-observing satellites) are constrained by the windows of visibility through the earth's atmosphere, even apart from clouds and haze. Earth-based infrared telescopes have the same constraints, hence one of the values of space telescopes.

7/12/2022, 12:50:24 PM

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Kelsey Jordahl

@kajord

Another really cool thing JWST can do is actually use that absorption to look at the composition of atmospheres of planets around other stars!

7/12/2022, 2:54:52 PM

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