Progress of the Chinese SONG Nodes

1. Progress of the Chinese SONG Nodes Xiaojun Jiang, Fei Zhao National Astronomical Observatories, Chinese Academy of Sciences 2010.03

2. Overview of Chinese standard and customized nodes • A preliminary design review • Site information • Candidate manufacturer(s) • Project schedule

3. Overview of Chinese nodes • Two nodes: Standard & Customized • Chinese Standard SONG Node • - Original SONG node + Wide Field 3-color Photometer • Why a customized node? • - General purpose photometric telescope • - Monitoring of variable objects

4. Why a customized node? (ctd.) - Ground follow-up observations - Participating observing campaigns and SONG’s microlensing program

5. Chinese Standard Node • Aperture：1m • Alt-Az • Classic Cassegrain • 2Nasmythplatforms • Lucky imaging • HRS + 3-color photometer • M1 & M2 make an F/37 beam • ~f/6.1 reducer, offers15’x15’ FOV • Pointing precision：5” RMS • Pointing speed ：20°/s Max • Dome: Φ ≈5.5m

6. Standard Node - Nasmythplatform 1 • to lucky imager • F/37 • ADC + optical derotator • Focus monitor • WL split @650nm for vis/red cameras

7. Standard Node - Nasmythplatform 2 • 3-color photometer • split by a folding mirror (M4) with central hole • F/37 – F/6.1 reducer • monitoring field stars around central target by using the 3-color photometer w/ 15’x15’ • 3-color: B、V、R • iKon-L 936: 2048*2048 (13um) • Mechanical derotator • HRS • as per standard SONG HRS design

8. Standard node: 3-color photometer • FOV :≧15’ x 15’ • Focal length≦6100mm w/ reducer • Image quality： • Encircled energy (80%) diameter : Ф40micron (each of the BVR bands) • 40micron corresponding to FOV of 1.4” @ F=6100mm

9. Ovserview of Chinese Customized Node • 1m, Alt-Az mount • M1 & M2 make a F/37 beam • M2& M3 offer a 24’x24’ FOV • two Nasmythplatforms • Lucky imager (Same as the Std node) • CCD photometer with 24’x24’ FOV • Pointing precision：5”RMS • Pointing speed ：20°/s Max • Dome: Φ ≈5.5m

10. Stray Light control Inner surface of each port between detector and M3 stray light stops Inner surfaces of the M2&M3 baffle ,Upside of the M1 aperture stop  knife-edged vanes Surfaces of baffles and M1 enclosure that can be seen by the detector directly  Enhanced black paint

11. Optical Design review

12. Achieved diffraction limit（λ/20RMS @633nm）over Φ6’ FOV with classic Cassegerain design – satisfy the requirement of LI

13. Difficulties: • High-power reducers for both nodes: two solutions • Layout of 3-color photometer for standard node: compromise or not?

14. High-power reducer: solution 1 • 6 elements in 6 groups • Max clear dia. 194mm (dense crown) • BFD: 35mm from the rear surface (need to be optimized) • Fits customized node after optimization

16. Vignetting less than 30% on the F/6.1 image

17. High-power reducer: solution 2Re-image Focal Reducer Intermediate pupil image (Lyot stop) Prism as beam splitter (Options for multi -channel photometry) Intermediate focal plane (Field stop) D=1010

18. Re-image Focal Reducer Re-image Focal Reducer --F/37 to F/6.1 --F/37 to F/6.1 Intermediate pupil image (Lyot stop) Prism as beam splitter (for multi-channel photometry) D=1010 Intermediate focal plane (Field stop) Folding mirror with central hole

20. Sumarry of re-image focal reducer • 9 lens in 9 groups • Front lens Φ=192mm, Dense Crown glass • Lens after that: • aperture diameters less than 110mm • Dense Crown and Dense flint glasses • BFD 146mm • 80% energy within Φ40um (FOV 15’x15’) in V band • Transmittance will be decreased by ≈30% • 3-color photometer’s layout is a critical issue

21. Summary of preliminary optical design • Optical quality of M1 + M2 meets the requirement of Lucky imaging; • The design of F/37-to-F/6 reducers for both nodes are feasible, but need further optimization; • Optical layout of the 3-color photometer in the standard node is a tough job, may need make compromise with astronomers – use 2-color or give up the simultaneity

22. Site Information in China

23. Changchun Urumqi NAOC Delingha PMO SHAO YNAO 2005.08.31 7 Xinglong(LAMOST) Miyun HuaiRou Urastai NIAOT FAST Gaomeigu

24. Site information in China High Vast Land Clean Dilute Air Less cloudy Cold, Dry Dark, Quiet Cloud distribution at 2:00BJT CMA 2425 stations 1961-2008, Y. Zhang et al Distribution of clear nights GMS + NOAA 1996 -2003, J. Mao et al 2004

25. Light pollution

26. Karasu: N38 10 E74 48, 4500m  2005.04 Karasu, Xinjiang airport & train station ↙ Kashi-Karasu : 190km ~ 2 hr Oma -Lhasa: 1000km ~ 2 days ⊙ 喀什 Oma 5000m Karasu 4500m 卡拉苏 ⊙ Oma: N32 32 E83 03, 5100m ⊙ 叶城  airport & train station ↙ 2005.08 Oma, Tibet ⊙ 物玛 阿里 ⊙ airport @2010 ⊙ 措勤 拉萨 ⊙ Site Survey carried out by NAOC

27. 2007.10 Karasu 2008.11 Oma Site 40 m CT2 tower 10mtower weather station DIMM seeing dome 40 m CT2 tower 4.5 m antenna Satellite communication weather station 10mtower DIMM seeing dome MIR cloud monitor MIR cloud monitor SBIG seeing monitor SBIG cloud monitor SBIG seeing monitor Renewal power supply Instrument setup & campaign

28. CASS 2009：new site for small telescopes

29. Candidate Manufacturersin China

30. Nanjing Institute of Astronomical Optics & Technology (NIAOT) • Nanjing Astronomical instruments Co.,Ltd (NAIRC) • Shanghai Astronomical Observatory (SHAO) • Changchun Institute of Optics, Fine Mechanics and Physics (CIOMP) • Institute of Optics and Electronics (IOE)

31. NIAOT is the unique  institute in China specialized in reserach and developing astronomical technology, professional astronomical telescopes and instruments. Major Projects Involved LAMOST FAST SST Antarctic Telescopes

32. Large sky Area Multi Objects Spectra Telescope (LAMOST) LAMOST is a quasi-meridian reflecting Schmidt telescope laid down on the ground with it’s optical axis fixed in the meridian plane. Theeffective aperture of LAMOST is 4m. It’s focal plane is 1.75m in diameter, corresponding to a 5 degree field of view, may accommodate as many as 4000 optical fibers. So the light from 4000 celestial objects will be led into 16 spectrographs.

33. LAMOST-Mb with 37 sub-mirrors

34. LAMOST-Ma with 24 sub-mirrors

35. 16 Low/MediumResolution Spectrographs RL = 1000/2000 RM= 5000/10000 4kx4k CCD, 12μ/pixel VPHG (Wasach optics ) First of 16 LRS Spectral range: Low blue: 370—590nm red: 570—900nm Medium blue: 510nm — 540nm red: 830nm — 890nm

36. Space Solar Telescope (SST) Main characters: 0.1"  0.15" space resolution for vector magnetic field and velocity field etc. 2D spectrograph magnetic analyzer with accuracy ~ 10-4 0.5" soft X-ray images at 4 bands simultaneously Optical design: Diameter: 1 M; Focal rate : 3.5 to 1, FoV : 2.8 ' x 1.5 ', Diffraction limit: 0.1"— 0.15“

37. 1）tube material：INVAR-36 • Tube sealed and filled with dry nitrogen • Tilted window with ITO (snow-removing and deicing) • Special damping structure for safe transportation

38. SONG-CHINA project schedule

39. May 2010: finish preliminary design of both nodes • December 2010: past design review ,place order of the telescopes/instruments • December 2011: finish site-testing • April 2012: start construction of enclosures/control rooms • December 2012：finish on-site installation and past acceptance tests, engineering runs • April 2013: science operations

40. Thank You !