Images delivered by FIRST. Left: Exposure of 100 ms and 50 EMgain of Keho‘oea, corrected from curvature. The vertical dark line around wavelength channel 50 corresponds to the telluric oxygen A band absorption line around 760 to 765 nm. Right: Power spectral density computed from 30 cubes of 100 acquisitions with 100 ms exposure and 50 EMgain. The white dots show the PSD peak fitting for some selected spectral lines.