Early Sciences & Test observations with LAMOST

1. Early Sciences &Test observations with LAMOST Yongheng Zhao National Astronomical Observatories of China

2. Characteristics of LAMOST • Effective aperture 3.6-4.9 meter • FOV 5（1.75m linear） • Number of fibers 4000 • Observing sky area -10   +90 • Spectral resolution R=1000/2000 (+5000/10000) • Survey capability spectral resolution 1nm, integration time 1.5 hours, magnitude limit: 20.5m • Size of fiber 3.30 arcsec（ 320 macro linear） • Site seeing: ~2 arcsec

3. Oct 20, 2007

4. Structure of LAMOST MA mirror Fiber Positioning Fibers MB mirror Spectrographs CCDs

5. Optical System

6. MB(~ 6.1m)

7. （July 13,2008) • Segmented Active optics for 37 sub-mirrors of MB

8. 24 sub-mirrors of MA （~ 4.9m）

9. （Sept. 10, 2008) • Segmented and thin mirror active optics for 24 sub-mirrors of MA

10. Image quality of LAMOST <1” Target: < 2” （Nov. 21, 2008)

11. At 5.2 degrees FOV Oct. 11, 2008

12. At 3.2 degree FOV • FWHM<10pixel, ~2 arcsec Apr.25, 2009 Image quality: 0.3-0.4 arcsec Seeing: 1.7-2 arcsec

13. Pointing< 5” Target: < 10”

14. Tracking 0.632“（80%） 0.52"（rms） Target: < 1”

15. Instruments • 4000 Fibers (130km) • 4000 Fiber positioning units • 16 Spectrographs • 250 fibers per spectrograph • 32 4k x 4k CCD Cameras • E2V CCD chips

16. Focal Plate for holding 4000 fibers Positioning unit with 2 step motors Double arm scheme

17. 4000 fiber positioning units

18. Repeat accuracy of 4000 units <0.14” target: <0.5”

19. 16 spectrographs 250 fibers per spectrograph RL = 1000/2000 RM= 5000/10000 Spectral range: Low blue: 370—590nm red: 570—900nm Medium blue: 510nm — 540nm red: 830nm — 890nm

20. 16 spectrographs

21. Relative efficiency of fiber to fiber （No.6 spectrograph-blue）

22. Efficiency of spectrograph 370~900nm • 43% (peak) • Target ：35%（peak）

23. Test Observations • Sept. 2008 – June 2009 • Test observations for check • Several dark nights in each month

24. Spectra of bright stars（28/9/2008） Blue Red

26. Apr.1, 2009 Galaxies (g>19)

27. Apr.1, 2009 QSOs (g>19)

28. Apr. 26, 2009 • Stars (V<19) • More than 3600 spectra got in one test observation (>90% of selected objects)

29. No.5: red No.4: red

30. Early Sciences Test observations for scientific WGs • Observations: 97 exposures (each 1.5h) • Oct. 2009: 20 for stars • Nov. 2009: 20 for stars, 6 for galaxies • Dec. 2009: 18 for stars, 10 for galaxies • Jan. 2010: 18 • Feb. 2010: 7

32. Oct. 26, 2009 M31 area

33. M31 • 17 new PNs • 19 confirmed two exp. in Oct. & Dec.

34. Beyond M31: 14 new QSOs：z<2

35. 8 New QSOs 1 exp. In Dec.

37. Candidates of metal-poor stars • 19 with S/N>15 • 9 with [Fe/H]<-1

38. Candidates of metal-poor stars • Pipeline  • 8 MP stars 1: [Fe/H]~-2.7

39. Improvement • Mar.-July • Positioning accuracy for 4000 fibers • Jul.-Sep. • Fine adjusting of spectrographs & CCDs • 2D pipeline

40. Positioning accuracy for 4000 fibers 2”  1”

41. M31 area Sep.11, 2010

42. Plan • Oct.-Dec. • Scientific test observations • Jan.-June • Test for scientific surveys

43. Thank You！

44. Positioning errors • “fiber scan”

45. July 6 • σx=1.7”, σy=2.3” ΔY (“) ΔX (“)

46. Positioning of 4000 fibers • Transformation of Coords. • 4000 coordinates for 4000 fibers • Fiber coords.  Focal plane coords • 4000（x0，y0，θ0） • FP coords.  CCD coords.（celetial） • Shift, rotation, expanding • Symmetric errors • measurement  correction

47. CCD0 CCD3 CCD2 CCD1 Coord. of 4000 fibers Coord. of 4 guiding CCDs

48. Celestial coords measured by 4 guiding CCDs CCD coords Fiber coords

49. July 6 • σx=1.7”, σy=2.3”  • σx=1.1”，σy=1.2”

50. Dome Seeing • 日期：20091122 • 天区：06faint • 中央星：124.7456700 56.2547100 7.00 3.70 -8.40 • Seeing：11*0.24= 2.64角秒（CCD：4033）（时间：04:30) • 日期：20091221 • 天区：sky5f • 中央星：91.0300674 23.2636089 5.09 0.00 0.00 • Seeing：8*0.24= 1.92角秒（CCD：6033）（时间：1:12)