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GTC 2009Jul251 TMT: the next generation of segmented mirror telescopes Jerry Nelson, UCSC GTC Inauguration Seminar 2009 July 25.

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Presentation on theme: "GTC 2009Jul251 TMT: the next generation of segmented mirror telescopes Jerry Nelson, UCSC GTC Inauguration Seminar 2009 July 25."— Presentation transcript:

1 GTC 2009Jul251 TMT: the next generation of segmented mirror telescopes Jerry Nelson, UCSC GTC Inauguration Seminar 2009 July 25

2 GTC 2009Jul252 Outline Project Introduction Telescope overview TMT key features Major science goals Science Instruments

3 GTC 2009Jul253 ALMA and ELTs 2009 3 TMT Mauna Kea Best high- altitude seeing 4200 m

4 GTC 2009Jul254 ALMA and ELTs 2009 A Mauna Kea Science Preserve Master Plan: Astronomy Precinct Proposed Site Area Mauna Kea 13N site NORTH Prevailing wind

5 GTC 2009Jul255 Project Introduction Time line –2004project start, design development –2009preconstruction phase –2011start construction –2018complete, first light, start AO science Partnership –UC –Caltech –Canada –Japan –NSF? –Other nations? Cost –970M$ (2009$)

6 GTC 2009Jul256

7 7 ALMA and ELTs 2009 What is TMT? Thirty-meter aperture Filled, segmented primary Elevation axis in front of primary Active and adaptive optics UV to thermal IR Broad range of instruments

8 GTC 2009Jul258 TMT features 14 - 200 times the sensitivity of 8 m telescopes (D 2 - D 4 gain) 3 - 5 times the resolution of 8 m telescopes and JWST 20 arcmin field of view 5 AO modes Pointing in < 3 min Instrument change in < 10 min Calotte enclosure

9 GTC 2009Jul259 Observatory Layout: Telescope Tensional members M2 hexagonal ring M2 support tripod M2 support columns Elevation journal M1 cellAzimuth truss Azimuth cradle M2 structural hexapod LGSF beam transfer LGSF launch telescope Nasmyth platform Laser room

10 GTC 2009Jul2510 TMT Optical Design: Ritchey Chrétien M1 Parameters –ø30m, f/1, Hyperboloid k = -1.000953 –Paraxial RoC = 60.0m –Sag = 1.8m –Asphericity = 29.3mm (entire M1) M2 Parameters –ø3.1m, ~f/1, Convex hyperboloid, k = -1.31823 –Paraxial RoC = -6.228m –Sag = ~650mm –Aspheric departure: 850  m M3 Parameters –Flat –Elliptical, 2.5 X 3.5m

11 GTC 2009Jul2511 Segment Size

12 GTC 2009Jul2512 Nasmyth Configuration: First Decade Instrument Suite

13 GTC 2009Jul2513 Why build a 30-m telescope: huge aperture advantage Seeing-limited observations and observations of resolved sources Background-limited AO observations of unresolved sources High-contrast AO observations of unresolved sources High-contrast ExAO observations of unresolved sources

14 GTC 2009Jul2514 Science Potential Solar system detailed studies Direct imaging planets around nearby stars Stars and stellar evolution Black holes and galaxies Nearby galaxies Distant galaxies and first light

15 GTC 2009Jul2515

16 GTC 2009Jul2516 Distant Galaxies – TMT+AO Credit: M. Bolte TMT with AO angular resolution 100x better than seeing limited

17 GTC 2009Jul2517 Primary Mirror Segments TMT segmented mirror is an evolution of the Keck mirror 36 segments, 1.8m, in each Keck telescope 492 segments, 1.45m, in TMT Polishing and segment module fabrication must be “mass produced” to cost and quality TMT is working with industrial partners to compete production design, testing and cost

18 GTC 2009Jul2518 Segment Support Assembly (SSA) Design Seven Segment Assembly – Top View

19 GTC 2009Jul2519 Segment Support Assembly (SSA) Design Seven Segment Assembly – Bottom View

20 GTC 2009Jul2520 Active Control Summary Selected a = 0.72 m for segment size ItemKeckTMT segment size0.9m0.72m # segments36492 # edge sensors1682772 # actuators1081476

21 GTC 2009Jul2521 Adaptive Optics

22 GTC 2009Jul2522 Adaptive Optics Adaptive optics seriously introduces the concept of high speed, high bandwidth control –Primary aim is to remove rapidly varying atmospheric turbulence that causes image blur –Secondary bi-product is ability to remove both slowly varying and rapidly varying wavefront errors that are in the telescope As currently envisioned and used, adaptive optics is only practical in the near infrared, not the visible. Adaptive optics is technologically challenging! Result is diffraction-limited performance –AO is revolutionary –For TMT resolution of 0.005 arcsec 100x better than atmosphere

23 GTC 2009Jul2523 Basic Elements of Adaptive Optics Atmospheric turbulence… introduces wavefront and image quality degradations… which can in principal be compensated by a wavefront corrector… provided that they can be measured with a wavefront sensor… observing a suitable reference star

24 90km Na layer (~10 km) 35 arcsec 30 m Turbulent atmosphere (~15 km) starlight Na Laser Tomography and MCAO Na laser beams (6 total) DM conjugate to h= 0 km DM conjugate to h ~ 10-12 km “Meta-pupil” for a +/-1 arc min FoV Light from 1 arcmin off axis

25 GTC 2009Jul2525 TMT AO NFIRAOS has two deformable mirrors- MCAO –64x64 –73x73 NFIRAOS laser will produce 6 laser spots –Illuminates Na layer, 90km up in the atmosphere –150 Watts Na power –One central spot, 5 perimeter spots Two arc minute field of view Atmosphere is tomographically reconstructed, then projected out in the direction of interest Computationally intensive –Solve 38000x7000 control problem at 800 Hz

26 GTC 2009Jul2526 TMT AO Early Light Architecture Narrow Field IR AO System (NFIRAOS) –MCAO LGS AO System –Mounted on Nasmyth Platform –Feeds 3 science instruments Laser Guide Star Facility (LGSF) –Laser enclosure located within telescope azimuth structure –Conventional optics for beam transport –Laser launch telescope behind M2 AO Executive Software (AOESW) NFIRAOS: - 190nm RMS WFS - 60x60 order system - 2 DMs, 6 LGS, 3 TTF WFS - 800Hz LSE

27 GTC 2009Jul2527 NFIRAOS Interfaces with Nasmyth Platform and Client Instruments BTO Path Nasmyth Platform Interface Electronics Enclosure LGS WFS Optics Optics Bench and Instrument Support Structure NFIRAOS Enclosure IRIS Future (third) Instrument Service Platform Nasmyth Platform

28 GTC 2009Jul2528 NFIRAOS Optics Benches

29 GTC 2009Jul2529 Science instruments

30 GTC 2009Jul2530 Instrument Spectral Resolution Science Case Near-IR DL Spectrometer & Imager (IRIS) ~4000 Assembly of galaxies at large redshift Black holes/AGN/Galactic Center Resolved stellar populations in crowded fields Astrometry Wide-field Optical Spectrometer (WFOS) 1000-5000 IGM structure and composition 21.5 galaxies suitable for measuring stellar pops, chemistry, energetics Near-field cosmology Multi-slit near-DL near-IR Spectrometer (IRMS) 2000 - 5000 Near-IR spectroscopic diagnostics of the faintest objects JWST follow-up Mid-IR Echelle Spectrometer & Imager (MIRES) 5000 - 100000 Physical structure and kinematics of protostellar envelopes Physical diagnostics of circumstellar/protoplanetary disks: where and when planets form during the accretion phase ExAO I (PFI) 50 - 300 Direct detection and spectroscopic characterization of extra-solar planets High Resolution Optical Spectrograph (HROS) 30000 - 50000 Stellar abundance studies throughout the Local Group ISM abundances/kinematics, IGM characterization to z~6 Extra-solar planets! MCAO imager (WIRC) 5 - 100 Precision astrometry Stellar populations to 10Mpc Near-IR, DL Echelle (NIRES) 5000 - 30000 Precision radial velocities of M-stars and detection of low-mass planets IGM characterizations for z>5.5 TMT First Decade Instrument/Capability Suite

31 GTC 2009Jul2531 Instrument Spectral Resolution Science Case Near-IR DL Spectrometer & Imager (IRIS) ≤4000 Assembly of galaxies at large redshift Black holes/AGN/Galactic Center Resolved stellar populations in crowded fields Astrometry Wide-field Optical Spectrometer (WFOS) 300 - 5000 IGM structure and composition 21.5 galaxies suitable for measuring stellar pops, chemistry, energetics through peak epoch of gal form. Multi-slit near-DL near-IR Spectrometer (IRMS) 2000 - 5000 Near-IR spectroscopic diagnostics of the faintest objects JWST followup Mid-IR Echelle Spectrometer & Imager (MIRES) 5000 - 100000 Physical structure and kinematics of protostellar envelopes Physical diagnostics of circumstellar/protoplanetary disks: where and when planets form during the accretion phase ExAO I (PFI) 50 - 300 Direct detection and spectroscopic characterization of extra-solar planets High Resolution Optical Spectrograph (HROS) 30000 - 50000 Stellar abundance studies throughout the Local Group ISM abundances/kinematics, IGM characterization to z~6 Extra-solar planets! MCAO imager (WIRC) 5 - 100 Galactic center astrometry Stellar populations to 10Mpc Near-IR, DL Echelle (NIRES) 5000 - 30000 Precision radial velocities of M-stars and detection of low-mass planets IGM characterizations for z>5.5 TMT Early Light Instrument Suite

32 GTC 2009Jul2532 IRIS - Infrared imaging spectrometer Grating IRIS dewar (at 77k) Common spectrograph and camera for both IFUs imager filter wheels F/15 AO Focus 2’ WFS imager IFUs

33 IRMS - Infrared multislit spectrometer 0.8 - 2.5 um cryogenic multi-slit spectrometer 2.3 arcmin field of view 0.06 arcsec sampling 46 moveable slits 2.4” long Covers entire Y, J, H or K band at R = 4660

34 WFOS - Wide-field optical spectrograph 0.31 - 1.1 um wavelength range Observe up to 1500 objects over a 40.5 sq. arcmin FOV Spectral resolution 300 - 7500 Reflecting gratings / prism cross-dispersion, and fixed dichroic beamsplitter at 550nm “Echellette” design provides up to 5 orders Full wavelength coverage, even at highest resolution, for “discovery science” Low resolution mode (single order) for maximum multiplex advantage

35 GTC 2009Jul2535 Summary TMT will be a 30-m telescope with AO capabilities from the start – ~ 190 nm rms wavefront error over 10 arcsec –First light 2018 Very large and exciting science case 8 instruments planned for the first decade 3 instruments planned for first light –IRIS (an AO NIR integral field spectrograph and imager) –IRMS (an AO NIR multi object spectrometer (46 slits) –WFOS (a seeing-limited multiobject spectrometer with R<8000, and ~ 50 arcmin 2 coverage)

36 GTC 2009Jul2536 www.tmt.org/foundation-docs/index.html Detailed Science Case 2007 Observatory Requirements Document Observatory Architecture Document Operations Concept Document TMT Construction Proposal –Currently in use for funding proposals TMT Foundation Documents


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