Fig. 1. Overall schematic of optical telescope

Fig. 2. Limitation test of 1.2 m large-aperture optical telescope. (a) Pointing path of telescope with curve indicating trajectory and straight line indicating pointing target of telescope; (b) tracking results of telescope

Fig. 3. Optical schematic of grating spectrometer

Fig. 4. Diagram of telescope with single-slit grating spectrometer. (a) Schematic of equipment assembly; (b) single-slit grating spectrometer mounted on optical telescope focus system

Fig. 5. Polaris spectra obtained by method one. (a) First observation; (c) second observation

Fig. 6. Spectrum of 5.80 magnitude star

Fig. 7. Optical schematic of fiber spectrometer

Fig. 8. Diagram of telescope with optical fiber spectrometer. (a) Schematic of equipment assembly; (b) terminal box with optical fiber through collimator; (c) front side of spectrometer

Fig. 9. Polaris spectra obtained by method two. (a) First round; (b) second round

Fig. 10. Measured spectra of stars with different magnitudes. (a1)(a2) 5 magnitude; (b1)(b2) 6 magnitude; (c1)(c2) 7 magnitude; (d1)(d2) 8 magnitude

Fig. 11. Optical schematic diagram of sCMOS camera imaging spectrometer with liquid crystal tunable filter

Fig. 12. Filter spectrometer camera. (a) Schematic of equipment assembly; (b) liquid crystal tunable filter; (c) sCMOS camera

Fig. 13. Polaris spectrum obtained by method three

Fig. 14. Images of target at different wavelengths

Fig. 15. Brightness of target in Fig. 14 versus wavelength

Fig. 16. Spectral data of GEO target. (a) First round; (b) second round