Early Sciences & Test observations with LAMOST
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Transcript of Early Sciences & Test observations with LAMOST
Early Sciences &Early Sciences &Test observations Test observations
with LAMOSTwith LAMOST
Yongheng ZhaoYongheng Zhao
National Astronomical Observatories of ChinaNational Astronomical Observatories of China
• Effective aperture Effective aperture 3.6-4.9 meter3.6-4.9 meter• FOVFOV 55 (( 1.75m linear1.75m linear ))• Number of fibers Number of fibers 40004000• Observing sky area Observing sky area -10-10 +90 +90 • Spectral resolution Spectral resolution R=1000/2000 (+5000/10000)R=1000/2000 (+5000/10000)• Survey capability spectral resolution 1nm,Survey capability spectral resolution 1nm,
integration time 1.5 hours,integration time 1.5 hours,
magnitude limit: 20.5magnitude limit: 20.5mm
• Size of fiber Size of fiber 3.30 arcsec3.30 arcsec ( ( 320 macro linear320 macro linear ))• Site seeing: ~2 arcsecSite seeing: ~2 arcsec
Characteristics of LAMOSTCharacteristics of LAMOST
Oct 20, 2007
Structure of LAMOSTStructure of LAMOST
MB mirror
Fiber Positioning
Fibers
MA mirror
Spectrographs
CCDs
Optical SystemOptical System
MBMB
(( ~ ~ 6.1m)6.1m)
Segmented Active optics Segmented Active optics for 37 sub-mirrors of MBfor 37 sub-mirrors of MB
(( July 13,2008)July 13,2008)
24 sub-mirrors of MA 24 sub-mirrors of MA (( ~ ~ 4.9m4.9m ))
Segmented and thin Segmented and thin mirror active optics for mirror active optics for 24 sub-mirrors of MA24 sub-mirrors of MA
(( Sept. 10, 2008)Sept. 10, 2008)
Statistics
0
5
10
15
20
25
30
0.1 0.3 0.5 0.7 0.9 1.1 1.3 1.5 1.7 1.9 2.1 2.3 2.5 2.7 2.9 3.1
EE80(arcsec)
Times
I mage Qual i ty vs I terat i on
0
5
10
15
20
25
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67I terat i ons
( 2 )每次迭代约 分钟
EE80
(arc
sec)
Image quality of LAMOSTImage quality of LAMOST
(( Nov. 21, 2008)Nov. 21, 2008)<1”<1”
Target: < 2”Target: < 2”
At 5.2 degrees FOVAt 5.2 degrees FOV
Oct. 11, 2008
At 3.2 degree FOVAt 3.2 degree FOV
FWHM<10pixel, FWHM<10pixel, ~2 arcsec~2 arcsec
Apr.25, 2009Apr.25, 2009
Image quality: 0.3-0.4 arcsecSeeing: 1.7-2 arcsec
PointingPointing< 5”< 5”
Target: < 10”Target: < 10”
TrackingTracking
0.632“ ( 80% )0.52" ( rms )
Target: < 1”Target: < 1”
InstrumentsInstruments
4000 Fibers (130km)4000 Fibers (130km) 4000 Fiber positioning units4000 Fiber positioning units 16 Spectrographs 16 Spectrographs
250 fibers per spectrograph250 fibers per spectrograph
32 4k x 4k CCD Cameras32 4k x 4k CCD Cameras E2V CCD chipsE2V CCD chips
Positioning unit with 2 step motors
Double arm scheme
Focal Plate for holding 4000 fibers
8.75
8.75
Ø41 2
34
单元1 单元2
26
4000 fiber positioning units4000 fiber positioning units
Repeat accuracy of 4000 unitsRepeat accuracy of 4000 units
<0.14”<0.14”
target: <0.5”target: <0.5”
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
16 spectrographs16 spectrographs
16 spectrographs16 spectrographs
Relative efficiency of fiber to fiber Relative efficiency of fiber to fiber (( No.6 spectrograph-blueNo.6 spectrograph-blue ))
Efficiency of spectrograph Efficiency of spectrograph 370~900nm370~900nm
43% (peak)43% (peak)
Target Target :: 35%35% (( peakpeak ))
Test ObservationsTest Observations
Sept. 2008 – June 2009Sept. 2008 – June 2009 Test observations for checkTest observations for check
Several dark nights in each monthSeveral dark nights in each month
Spectra of bright starsSpectra of bright stars (( 28/9/20028/9/20088 ))
Blue Red
Apr.1, 2009Apr.1, 2009
GalaxiesGalaxies
(g>19)(g>19)
Apr.1, 2009Apr.1, 2009
QSOsQSOs
(g>19)(g>19)
Apr. 26, 2009Apr. 26, 2009
Stars (V<19)Stars (V<19)
More than 3600 spectra got in one test More than 3600 spectra got in one test observation (>90% of selected objects)observation (>90% of selected objects)
No.4: red
No.5: red
Early SciencesEarly Sciences
Test observations for scientific WGsTest observations for scientific WGs Observations: 97 exposures (each 1.5h)Observations: 97 exposures (each 1.5h)
Oct. 2009: 20 for starsOct. 2009: 20 for stars Nov. 2009: 20 for stars, 6 for galaxiesNov. 2009: 20 for stars, 6 for galaxies Dec. 2009: 18 for stars, 10 for galaxies Dec. 2009: 18 for stars, 10 for galaxies Jan. 2010: 18Jan. 2010: 18 Feb. 2010: 7Feb. 2010: 7
Oct. 26,Oct. 26,
20092009
M31 areaM31 area
M31M31 17 new PNs17 new PNs 19 confirmed19 confirmed
two exp. in Oct. & Dec.two exp. in Oct. & Dec.
Beyond M31:Beyond M31:14 new QSOsnew QSOs :: z<2z<2
8 New QSOs8 New QSOs1 exp. In Dec.
Candidates of metal-poor starsCandidates of metal-poor stars 19 with S/N>1519 with S/N>15 9 with [Fe/H]<-19 with [Fe/H]<-1
Pipeline Pipeline 8 MP stars8 MP stars
1: [Fe/H]~-2.71: [Fe/H]~-2.7
Candidates of metal-poor starsCandidates of metal-poor stars
ImprovementImprovement
Mar.-JulyMar.-July Positioning accuracy for 4000 fibersPositioning accuracy for 4000 fibers
Jul.-Sep.Jul.-Sep. Fine adjusting of spectrographs & CCDsFine adjusting of spectrographs & CCDs 2D pipeline2D pipeline
Positioning accuracy for 4000 fibersPositioning accuracy for 4000 fibers
2” 2” 1” 1”
M31 areaM31 area
Sep.11,Sep.11,
20102010
PlanPlan
Oct.-Dec.Oct.-Dec. Scientific test observationsScientific test observations
Jan.-JuneJan.-June Test for scientific surveysTest for scientific surveys
Thank YouThank You !!
Positioning errorsPositioning errors
““fiber scan”fiber scan”
July 6July 6 σxσx==1.7”1.7”, , σyσy==2.3”2.3”
ΔX (“)
ΔY
(“)
Positioning of 4000 fibersPositioning of 4000 fibers
Transformation of Coords. Transformation of Coords. 4000 coordinates for 4000 fibers4000 coordinates for 4000 fibers Fiber coords. Fiber coords. Focal plane coords Focal plane coords
• 40004000 (( xx00 ,, yy00 ,, θθ00 )) FP coords. FP coords. CCD coords. CCD coords. (( celetialceletial ))
• Shift, rotation, expandingShift, rotation, expanding
Symmetric errorsSymmetric errors measurement measurement correction correction
CCD3
CCD0CCD2
CCD1
Coord. of 4000 fibersCoord. of 4000 fibers
Coord. of 4 guiding CCDsCoord. of 4 guiding CCDs
Celestial coords measured by 4 guiding CCDsCelestial coords measured by 4 guiding CCDs
CCD coordsCCD coords
Fiber coordsFiber coords
July 6July 6 σxσx==1.7”1.7”, , σyσy==2.3” 2.3” σxσx==1.1”1.1” ,, σyσy==1.2”1.2”
Dome SeeingDome Seeing
日期:日期: 2009112220091122 天区:天区: 06faint06faint 中央星:中央星: 124.7456700 56.2547100 7.00 3.70 -8.40124.7456700 56.2547100 7.00 3.70 -8.40 SeeingSeeing :: 11*0.24= 11*0.24= 2.642.64 角秒角秒(( CCDCCD :: 40334033 )(时间:)(时间:
04:30)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)
光纤偏离和视宁度对极限星等的光纤偏离和视宁度对极限星等的影响影响
光纤偏离光纤偏离------------------------
视宁度视宁度
0”0” 1”1” 2”2” 3”3” 4”4” 5”5”
1”1” 0.0m0.0m 0.1m0.1m 2.0m2.0m 8.0m8.0m
2”2” 0.2m0.2m 0.4m0.4m 1.6m1.6m 3.7m3.7m 7.0m7.0m
3”3” 0.6m0.6m 0.8m0.8m 1.6m1.6m 2.7m2.7m 4.3m4.3m 6.7m6.7m
4”4” 1.0m1.0m 1.1m1.1m 1.8m1.8m 2.5m2.5m 3.5m3.5m 4.8m4.8m
5”5” 1.4m1.4m 1.5m1.5m 2.0m2.0m 2.4m2.4m 3.2m3.2m 4.1m4.1m
圆顶杂散光测量圆顶杂散光测量33 月月 99 日日 33 月月 1010 日日
光谱光谱仪仪
IscIsc Isc+IsIsc+Iskk
Isc/IsIsc/Iskk
IscIsc Isc+IsIsc+Iskk
Isc/IsIsc/Iskk
1010 147147 911911 19%19% 113113 887887 14 %14 %
1111 168168 809809 26%26% 133133 705705 23 %23 %
1212 153153 827827 22%22% 121121 720720 20 %20 %
1313 156156 798798 24%24% 129129 705705 22 %22 %
1414 143143 900900 18%18% 114114 784784 17 %17 %
1515 9494 570570 19%19% 7878 581581 15 %15 %
1616 9292 757757 13%13% 127127 795795 19 %19 %
光纤对准测定光纤对准测定单高斯单高斯拟合:拟合:
xx00 ,, yy00
FWHMFWHM
FF**, Fb, Fb
焦平面调整(焦平面调整( 33 月)月)
光轴光轴 ++ 焦平面焦平面 共面共面
S-HS-H 中心(焦点)中心(焦点) 40004000 光纤端面光纤端面 44 导星导星 CCDCCD 靶面靶面