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Status of LAMOST
The Large Sky Area Multi-Object Fiber Spectroscopic Telescope
Structure of LAMOST
Fiber
Positioning
MA
mirror
Fibers
MB
mirror
Spectrographs
CCDs
Optical System
Basic parameters of LAMOST
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4.5m/6.3m Schmidt telescope
The declination of observable sky area ranges
from -10 to +90.
20 square degree of the FOV
4000 fibers
Spectrum resolution:
VPH (Volume Phase Holographic) Grating
R=1000, 2000, 5000, 10000
General Situation of the
Project
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The LAMOST project has its management
under National Astronomical Observatories
(hereafter NAOC) with its project office in the
headquarter of NAOC, and its main workforce
distributed in the Nanjing Institute of
Astronomical Optics and Technology /NAOC
in Nanjing, the Beijing part of NAOC and in
the University of Science and Technology of
China in Hefei. The project has its board and
scientific and technical committee as usual.
Xinglong Station, NAOC
the site
Beijing: NAOC
Project HQ
Instruments & Software
Science
Nanjing: NIAOT (NAOC)
Telescope
Instruments
Hefei: USTC
Science
Schedules of LAMOST Project
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Proposal
Feasibility Study
Preliminary Design
Detailed Design
Construction
First Light
Reviewed
Approved
Nov. 1996
Jul. 1997
Apr.-May 1999
Apr. 1997
Aug. 1997
Jun. 1999
Sep. 2001
2001-2008
2008.10
MA: 5.72mx4.4m reflecting corrector (24 submirrors)
MB: 6.67mx6.05m spherical mirror (37 submirrors)
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Technical Challenges of Active
Optics
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A combination of segmented mirror active
optics and thin deformable mirror active
optics on one mirror
Two large segmented mirrors needed to
be actively controlled in the same time in
the telescope.
With hexagonal deformable sub-mirrors.
Wave front sensing on a variable
aperture
Active optics & supporting
MB
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37sub-mirrors of MB （July 13,2008)
24 sub-mirrors of MA
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24 sub-mirrors of MA （Sept. 10, 2008)
Statistics
9
Oct. 8, 2008
8
7
6
5
Times
EE80(arcsec)
Image Quality vs Iteration
4
9
3
8
2
7
1
6
0
0.5 0.6 0.7 0.8 0.9
5
1 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9
2 2.1
EE80(arcsec)
4
Image Quality vs Iteration
3
2.5
2
1
0
1
4
7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55
Iterations
Mean=1.14″, Maintenance Mean=1.00″
80%=1.21″, 80% Maintenance=1.14″
EE80(arcsec)
2
1.5
1
0.5
0
1
4
7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52
Iterations
(每次迭代时间3.5分钟)
At 5.2 degrees FOV
multi-optical fiber positioning
Fiber positioning unit
4000 fiber position units
16 Spectrographs
LAMOST-LRS Optical System
Blue (370~590nm)
R5000/10000
R1000/2000
Red (570~900nm)
R5000/10000
R1000/2000
Resolution powers
Grating
1000
5000
Blue
branch
Red
branch
R
binning
500
3700-
5700-
-
1000
5900 Å
9000Å
narrow
slit
narrow
slit
2000
5100-
8300-
5400Å
8900Å
5000
10000
Spectrographs
VPHG (Volume Phase Holographic
Grating)
E2V-CCD203
南京
兴隆
红区
蓝区
Resolution of the spectrum
Operation software
Input
Catalog
SSS
OCS
TCS
ICS
LAMOST
DHS
Spectr.
Database
Software for
automatic observation & data processing
DPS
SSS
catalogue
processing
OCS
observation
First light of the small system
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On May 20 2007 The LAMOST small
system (about 2m in diameter and have
250 firbers) got its first spectrum!
Sky
白天天光观测
5月25日15时
6月5日18时
天光光谱
Select the targets
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Field No. 9
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June 22, 02h
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203 targets
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3600
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123 Spectrum
Component & Total Efficiency
Efficieny
1.00
0.80
telescope
fiber
0.60
Spectrograph
0.40
CCD
0.20
total
0.00
370
450
550
650
Wavelength(A)
750
850
Efficincy
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R波段
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Observe data ( Sky)：12.0%
Theoretical value： 16.5%
中值为1
July 2008
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MB: all 37 sub-mirrors
MA: all 24 sub-mirrors
Co-focus for MB: <0.4”
To test active optics
Spectrographs: 16
Fiber positioning units: 4000
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Wireless control system has tested
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August 24：4000optical fibers
completed
August 30：16 spectrographs
completed
 LAMOST completed all hardware
Test spectra (Aug.5, No. 3号spectrograph）
Blue
Red
Relative efficiency（No.6 spectrograph-blue）
Efficiency of spectrograph
370~900nm
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Target ：35%（peak）
According to test on reach parts: 50%
According to test on whole spectrograph: 43%
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Sept. 28
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More than 2000 spectra got in one test
observation
Oct. 13
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About 3000 spectra got in one test
observation
Spectra of stars（28/9/2008）
Red
Blue
Plan
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2009: Technical commission period
2010: Scientific commission period
2011: start regular spectroscopic survey
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2009:
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Stability
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Efficiency
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Active optics
Dome seeing
Fibers
Spectrographs
CCDs
Scientific observations
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Open clusters, M31, selected area survey, …
regular spectroscopic survey
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2010-2015
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Working groups for
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Extragalactic survey
Galactic survey
input catalog for LAMOST
(end of 2009)
SDSS
2DF
LAMOST
Aperture
2.5m
4m
4m
Field of View
3
2
5
Number of
Fiber
640
400
4000
Spectral
resolution
1800-2100
1000
1000-2000, 5000-10000
Spectral
ranges（Å）
3900-6100
6000-9100
3600-8000
3700-6200
6000-9000
Diameter of
Fiber
3 ”(180mu)
2.16”(140mu)
3 ”(320mu)
Mini Distance
of Fibers
55 ”
12 ” (30”)
S/N
4.5/pix (g=20.2)
13/pix (mean)
11/pix (20.5, 1.5h)
Limited
Magnitude
i=15-19.1,20.2(q)
r<17.7(g)
bj 18.25-20.85(q)
B<20.5
Fiber Position
Accuracy
0.5 ”
bj 17-19.45(g)
Sqrt(1 ”+0.25”^2)~1.03”
5100-5400
8300-8900
40 ”
0.5”(3 sigma)
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LAMOST will become the most effective
spectroscopic survey telescope, and the
most powerful facilities for researches
of wide field of view and large sample
astronomy.
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LAMOST is a National large
astronomical instrument, it will open to
all Chinese Astronomer.
We make the first call for observational
proposal (2008-04)
How can we do better than
2dF and SDSS?
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Large Aperture
Large field of view
More fibers
But XingLong station ??
Weather at Xinglong Site
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Average temperature 7~8℃, lowest -22.5℃, highest
33.0℃
94%(332 days) daily temperature difference less than
12℃
Average wind speed 2.4m/s~3.1m/s . About 90 days in a
year instant wind speed >8m/s
Yearly average relative humidity 57%, about 5.7%(21
days), RH > 90%. Precipitate days ~20 days/yr
Observing nights ~200 nights/yr
Seeing by BATC
Seeing by BATC
Seeing ~ 2” -3”
Extinction
Kv ~0.1 -0.33
Sky Brightness
Mv ~ 20.5 -21.5 /sq. degree
Key Projects
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Extra-galactic spectroscopic survey —
Galaxy and QSO redshift survey
Stellar spectroscopic survey —
Structure of the Galaxy, and so on.
Cross identification of multi-waveband
survey.
Extra-galactic
spectroscopic survey —
Galaxy and QSO
redshift survey
Magnitude limited sample
• North Galactic Pole region:
~7700 degree2 r<18.8 ~2.6X106 gal.
• South Galactic Pole region:
~4000 degree2 r<19.5 ~2.6X106 gal.
Redshift survey of Galaxy
Low Resolution spectroscopy:
• To obtain the spectra of faint celestial
objects (Galaxy and AGN) with R=1000
spectral resolution, S/N=10.
• Wavelength range: 370—900 nm
• From SDSS DR6 data select about
2.6X106 galaxies
Luminous Red Galaxy (LRG)
galaxies survey:
i< 20.0
~1.5X106 gal.
LRG sample
Advantage to select LRG
• Red color → easy to find the candidate
• Most luminous galaxy → Map large
cosmological volume
• Correlated with cluster
→ To detect and study the clustering
QSO survey
• Combine the high quality digital image
data of SDSS (5 colors) with powerful
spectroscopic capabilities of LAMOST to
conduct a deep wide field spectroscopic
suevey for Quasars
Deep survey
• Select few 100 degree2 field
deep spectroscopy survey to
i~ 20.5
The mean redshift is about Z=0.3, Some of
these sample could go to as deep as
Z=0.5
Deep Field selected
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RA (2000)
COSMOS field：
10:00:00
AKARI NEP
18:00:00
Lockman-Hole field：
10:47:00
H1K field：
14:00:00
ELAIS-North1 field：
16:11:00
DEC(2000)
02:12:00
+66:36:00
58:02:00
00:00:00
55:00:00
A detailed scientific case
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Studies of large-scale structure
Baryon Acoustics Oscillations => Dark energy
Formation and evolution of galaxies
AGN physics
The relation between galaxies and the IGM
Constrain dark energy from cluster counts and
Alcock-Paczsynki test
– Accurately measure luminosity functions & starformation rate densities with redshift &
environment
– Detailed studies of local low-luminosity galaxies
The structure and Evolution of
The Milk Way
• To get spectrum of 5×106 stars.
• Sloan Extension for Galactic Underpinnings and
Evolution (SEGUE) obtain ~ 250,000 spectra of
Galactic stars
• Stellar spectroscopy plays a crucial role in the
study of our Galaxy, not only providing a key
component of the 6-dimensional phase space of
stellar positions and velocities, but also
providing much-needed information on the
chemical composition of individual stars. Taken
together, information on space motion and
composition can be used to unravel the
formation process of the Galaxy.
LAMOST Accuracies and our Galaxy
+
Welcome you to use
LAMOST in the future