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

5. Chinese Standard Node Aperture ： 1m Alt-Az Classic Cassegrain 2 Nasmyth platforms ① Lucky imaging ② 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 - Nasmyth platform 1 – to lucky imager F/37 ADC + optical derotator Focus monitor WL split @650nm for vis/red cameras

7. Standard Node - Nasmyth platform 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 Nasmyth platforms ① Lucky imager (Same as the Std node) ② CCD photometer with 24’x24’ FOV Pointing precision ： 5”RMS Pointing speed ： 20°/s Max Dome: Φ ≈5.5m

10. 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 Stray Light control

11. Optical Design review

12. Achieved diffraction limit （ λ/20RMS @633nm ） over Φ 6’ 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. Re-image Focal Reducer High-power reducer: solution 2 Re-image Focal Reducer Intermediate focal plane (Field stop) Intermediate pupil image (Lyot stop) Prism as beam splitter (Options for multi -channel photometry) D=1010

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

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. 2005.08.317 Delingha Urumqi YNAO SHAO Changchun NAOC PMO Xinglong(LAMOST) Miyun HuaiRou NIAOT Urastai FAST Gaomeigu

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

25. Light pollution

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

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

28. CASS 2009 ： new site for small telescopes CASS 2009 ： new site for small telescopes

29. Candidate Manufacturers in 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. The effective 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/Medium Resolution Spectrographs R L = 1000/2000 R M = 5000/10000 4kx4k CCD, 12μ/pixel VPHG (Wasach optics ) Spectral range: Low blue: 370—590nm red: 570—900nm Medium blue: 510nm — 540nm red: 830nm — 890nm First of 16 LRS

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: Optical design: Diameter: 1 M; Diameter: 1 M; Focal rate : 3.5 to 1, Focal rate : 3.5 to 1, FoV : 2.8 ' x 1.5 ', FoV : 2.8 ' x 1.5 ', Diffraction limit: Diffraction limit: 0.1" — 0.15 “ 0.1" — 0.15 “

37. 1 ） tube material ： INVAR-36 2) Tube sealed and filled with dry nitrogen 3) Tilted window with ITO (snow-removing and deicing) 4) 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 !