1. YunNan One Meter Infrared Solar Tower Jun Lin

2. Why is YNST? After Solar-B launch, what can we do by using of ground-based telescope ? Detailed chromosphere diagnostics Special magnetic field observations (IR, hyperfine-structure of atoms) Higher angle resolution ----- B. W. Lites ( at THEMIS user meeting )

3. What is YNST? An optical system of 1-meter aperture: resolution < 0.3 arcsec (200 km), vacuum tube, AO Symmetric structure for accurate measurement of magnetic field: Gregorian telescope, 10 -4 polarization analyzer, I, Q, U, V Focal instrument of high resolution: Filter-based image Fabry-Perot filter, magnetograph, high spectral resolution Multi-wavelength observations: Multi-wavelength spectrograph, Near-Infrared detectors High accuracy tracking and pointing system: Auto guiding system, correlating tracker

4. YNST’s Spectral Range The Sun will be observed within the range from 3,000 to 25,000 Å. This range spans the spectrum from UV to near IR. Information includes those of the photosphere, the chromosphere, and the corona. Spectral lines include both magnetic field and plasma flow sensitive ones.

5. Location of the FUXIAN LAKE Fuxian lake

6. Look at the Fuxian Lake from Space

7. General Information of Fuxian Lake & Cape Eagel The distance from Kunming City: 60 km Altitude: 1712 m Longitude: 102°57'11" Latitude: 24°34'47" Maximum Width: 11.5 km Maximum Length: 31.5 km Maximum Depth: 155.0 m Surface Area: 211.0 km 2 Number of Clear Days/year: > 275 Average Wind Speed: < 6 m/s Water Integration : 11mm (average over a year) Average r 0 : 12.3 cm (average over a year), 11.5 cm ( median of a year)

8. Observatory Site Looking from Distance

9. N E S W

10. YNST

11. Internal and External Structures of the Building for YNST

12. YNST’s Optical System

13. Parameters for Each Component (F /45.9 Modified Gregorian System ) Window glass: H = 65 mm, D = 1,200 mm M1 : D = 980 mm, F/2.45 (paraboloid) M2 : D = 257.8 mm, F/9 (ellipse,-0.327) M3 : D = 234.3 mm, F/45.9 (ellipse,-0.453) M4 : 43.4 mm × 65 mm (flat) Exit pupil: D = 152 mm M5 View field: 3 arcmin Alt-azimuth mount, friction transmission

14. Spectrograph and Other Instruments Multi-wavelength spectrograph Other instruments H  6563 CaII 8542 HeI 10830 To adaptive lab

15. Parameters for Spectrometer Grating constant: 1200 g/mm; Blaze angle: 36 °48'; Incident angle: 33.5  Collimating concave mirror f = 6000 mm Focusing concave mirror f = 5000 mm LinesOrders Wavelength(Å) Diffraction Angle(°) Linear Dispersion(Å/mm) HeD 3 1 5878 8.81 1.647 H  1 6563 13.63 1.620 CaII 1 8542 29.18 1.455 ( Filter-based image, absence in ONSET ) HeI 1 10830 48.39 1.107 FeXIII ? 10746+10798 ? ? H  2 3646 18.85 1.577 K+H 2 3934+3968 23.08 1.533 H  2 4861 37.93 1.315 D 1, 2 2 5885 59.13 0.855 G-band ? 4300~4310 ? ? Fe I ? 6301.5+6302.5 ? ?

16. Spectral Lines of Interest (Ph+Ch) FeI (6301.5+6302.5): Photospheric line sensitive to magnetic field. H  : Traditional line used to observe flares. CaII (8542): Chromospheric line sensitive to magnetic field. HeI (10830): Good for observations of the filament magnetic field.

17. YNST’s Scientific Goals & Tasks Observational data of high resolutions in both time and space for magnetic field of fine structures. Properties of tiny fibrils, or flux tubes of kilo-gauss magnetic field. Coupling of magnetic field and mass motions, and energy transportation from the photosphere to the corona. Conducting multi-wavelength observations and data analyses; providing forefront observational data and opportunities to the research communities.