Aperture correction from the GSPC P330-E 220 G–dwarf. Left panel: flux fraction as a function of the aperture radius (NIRSpec/IFU, G395H/F290LP), that is, the cumulative PSF. Note that the PSF width increases going from blue to red wavelengths. The differences are larger for small radii, as the PSF profile is steeper. The curves are based on observations of the G-dwarf GSPC P330-E used for a Cycle 1 calibration program (ID: 1538). Right panel: Flux fractions for apertures with radii R = 0.1″ − 0.7″ as a function of the observed wavelength (NIRSpec/IFU, G395H/F290LP). The second-order spline fitted to the data is shown in yellow. The flux fraction decreases with increasing wavelength, especially at small radii.