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Hubble Space Telescope
COS 2025

Resolution vs Wavelength for COS FUV settings at LP4

The figure above shows the spectral resolution R=λ/Δλ versus wavelength for seven central wavelengths (cenwaves), five from the G130M grating (1055, 1096, 1222, 1291, and 1327) and two from the G160M grating (1577 and 1623). The two blue mode settings (1055 and 1096) remain at Lifetime Position 2 (LP2). All other settings shown are now at LP4. The resolution curves shown are generated by the Code V optical model, which has been validated at LP4 through on-orbit observations. Notice how the resolution increases with wavelength for the 1291, 1327, 1577, and 1623 settings.


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