1 / 48

Test observations with LAMOST

Test observations with LAMOST. Yongheng Zhao National Astronomical Observatories of China. Characteristics of LAMOST. Effective aperture 3.6-4.9 meter FOV 5  （ 1.75m linear ） Number of fibers 4000

maine
Download Presentation

Test observations with LAMOST

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 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. Enclosure Oct 20, 2007

  4. MB(~ 4.9m)

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

  6. 24 sub-mirrors of MA （~ 4.9m）

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

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

  9. At 5.2 degrees FOV Oct. 11, 2008

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

  11. Pointing< 5” Target: < 10”

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

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

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

  15. 4000 fiber positioning units

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

  17. 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

  18. 16 spectrographs

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

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

  21. Test Observations • Sept. 2008 – June 2009 • Test observations for check • Oct. 2009 – Jan. 2010 • Test observations for scientific WGs • Several dark nights in each month

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

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

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

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

  26. No.5: red No.4: red

  27. 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 • Data quality is not good

  28. Oct. 26 M31 area

  29. M31 • 17 new PNs two exp. in Oct. & Dec.

  30. Beyond M31: 14 new QSOs

  31. 8 New QSOs 1 exp. In Dec.

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

  33. 8 MP stars [Fe/H]~-2.7

  34. Main tasks Now • Positioning accuracy of 4000 fibers • 2-3” (target: 0.5”) • Efficiency of FP Instruments • 16 spectrographs • 32 CCD cameras • 2D pipeline • Sky subtraction

  35. Positioning errors • “fiber scan”

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

  37. 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

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

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

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

  41. Plan • July-Sep. • Positioning accuracy for 4000 fibers • Fine adjusting of spectrographs & CCDs • 2D pipeline • Oct.-Dec. • Scientific test observations • Jan.-June • Test for scientific surveys

  42. Thank You！

  43. 视宁度（导星CCD测量） • 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)

  44. 光纤偏离和视宁度对极限星等的影响

  45. 光纤对准测定 单高斯 拟合： x0，y0 FWHM F*, Fb

  46. 焦平面调整（3月） • 光轴+焦平面 • 共面 • S-H中心（焦点） • 4000光纤端面 • 4导星CCD靶面

  47. 圆顶杂散光测量

More Related