Fig. 1. Far ultraviolet radiation intensity of ionosphere. (a) At day; (b) at night

Fig. 2. Two-side lateral limb observation

Fig. 3. Optical design layout

Fig. 4. Optical design results. (a) RMS spot radius versus wavelength; (b) MTF at 130 nm; (c) MTF at 150 nm; (d) MTF at 180 nm

Fig. 5. Tolerance analysis system. (a) Optical elements; (b) opto-mechanical structure

Fig. 6. (a) Experimental system used for irradiation calibration; (b) spectral radiance responsibility of system

Fig. 7. (a) Spectrum of deuterium lamp; (b) spectral calibration of instrument in far ultraviolet waveband

Fig. 8. Detected waveform for 171 nm wavelength

Fig. 9. (a) Image plane; (b) spatial resolution test result