  On August 21, 2017, the Airborne Infrared Spectrometer (AIR-Spec) observed
the total solar eclipse at an altitude of 14 km from aboard the NSF/NCAR
Gulfstream V research aircraft. The instrument successfully observed the five
coronal emission lines that it was designed to measure: Si X 1.431 $\mu$m, S XI
1.921 $\mu$m, Fe IX 2.853 $\mu$m, Mg VIII 3.028 $\mu$m, and Si IX 3.935 $\mu$m.
Characterizing these magnetically sensitive emission lines is an important
first step in designing future instruments to monitor the coronal magnetic
field, which drives space weather events as well as coronal heating, structure,
and dynamics. The AIR-Spec instrument includes an image stabilization system,
feed telescope, grating spectrometer, and slit-jaw imager. This paper details
the instrument design, optical alignment method, image processing, and data
calibration approach. The eclipse observations are described and the available
data are summarized.
