Wavelengths for observed objects -- emitted or observed? The WISE craft (Widefield Infrared Survey Explorer) surveys the sky in 4 wavelength bands; 3.4, 4.6, 12, and 22 $\mu$m. When it's observing an object with an estimated redshift (given by 

$z = \frac{\lambda_{obs} - \lambda_{emit}}{\lambda_{emit}}$

from Wikipedia) of, say, 0.373 (the lowest redshift for one of the objects I'm studying), would the wavelength it's seen in be its observed wavelength? I'm interested in calculating the wavelength actually emitted by the object.
If the redshift is $z$, then the wavelength of light you observe is at a wavelength that is $1+z$ times longer than the wavelength emitted in the frame of reference of the galaxy.

In this case $z=0.373$, so when you observe light centered on say the 3.4 micron band, then the light was emitted at a wavelength of 3.4/1.373 microns.