Robo-AO: an autonomous laser adaptive optics and science system · 2011-09-02 · Demonstrate an autonomous, laser adaptive optics and visible/NIR science system on a 1.5-m ... on

Robo-AO: an autonomous laser adaptive optics and

science system

Christoph Baranec (PI)on behalf of the Robo-AO collaboration partners at

the Inter-University Centre for Astronomy and Astrophysics and the California Institute of Technology

Robo-AO

Caltech’s 1.5 m P60telescope at

Palomar Observatory

IUCAA’s 2 m telescope at Girawali Observatory

Robo-AO mission

Demonstrate an autonomous, laser adaptive optics and visible/NIR

science system on a 1.5-m telescope

Emphasis on robustness

Replicate and deploy this system around the world

Robo-AO has unique capabilities


• Robotic/autonomous operation– Very efficient, intelligent queue observing– 150 targets/night (~2 minute observations)



• Diffraction-limited resolution (mV<17)– ~0.1-0.15” in the visible– ~0.2-0.25” in the near-infrared




• 0.5+ Strehl in the near-infrared (30% sky)




• 0.5+ Strehl in the near-infrared (30% sky)• Seeing improvement (100% sky)




• 0.5+ Strehl in the near-infrared (30% sky)• Seeing improvement (100% sky)• Up to 2’ field of view (set by optical relays)




• 0.5+ Strehl in the near-infrared (30% sky)• Seeing improvement (100% sky)• Up to 2’ field of view (set by optical relays)• Range of filters, exposure times, setups, etc.

SNR improves with AO

• Astrometric precision gains in both SNR and FWHM

• Prediction: 100µas precision in around 15 minutes»(based on Cameron et al. Keck & Palomar performance)

Band SNR Compared to 1.5 m

FWHM (1” is typical)

Strehl

J 2.9X 0.2” 50%

H 7.1X 0.26” 70%

Traditional (Laser) Guide Star Adaptive

Optics

Robo-AORobotic Laser Guide

Star AO

Telescope diameter 3-10m 1.5-3m

Observing bands Infrared Visible + Infrared

Lock-on time 5-15 min / target 0.5-1 min / target

Targets per night Tens Hundreds

Program length Few nights Weeks+

Targets per program ~100 Thousands+

Personnel1 astronomer +

6 spotters + 2 telescope control

1 astronomer

(peacefully sleeping)

Robo-AO ushers in a newadaptive optics observing paradigm


Optics


Star AO









1 astronomer




Optics


Star AO









1 astronomer




Optics


Star AO









1 astronomer




Optics


Star AO









1 astronomer




Optics


Star AO









1 astronomer




Optics


Star AO









1 astronomer




Optics


Star AO









1 astronomer



Robo-AO enables new science

Large single-image surveysSeveral thousand targets, all at high-angular resolutionOtherwise extremely time intensive on currently available LGS AO systemsE.g. stellar binarity surveys, searches for lensed quasars, planetary transit follow up


Large single-image surveysSeveral thousand targets, all at high-angular resolutionOtherwise extremely time intensive on currently available LGS AO systemsE.g. stellar binarity surveys, searches for lensed quasars, planetary transit follow up

Einstein Cross (HST)(1.6 arc sec top to bottom)


Rapid transient characterizationDiffraction limited images within minutes of detection of transients (e.g. PTF, PTF-2, LSST) Reduction of integration time for infrared photometryE.g. separation of transient events from host galaxy

SN 2006GY

PTF transient


Rapid transient characterizationDiffraction limited images within minutes of detection of transients (e.g. PTF, PTF-2, LSST) Reduction of integration time for infrared photometryE.g. separation of transient events from host galaxy

SN 2006GY

Old New Difference

PTF transient


Time-domain astronomyQueue supports recurrent, regularly spaced observations of specific targetsE.g. long-term, high-precision astrometric characterization of sub-stellar companions


Time-domain astronomyQueue supports recurrent, regularly spaced observations of specific targetsE.g. long-term, high-precision astrometric characterization of sub-stellar companions

Trent Dupuy 2008, 2009

Robo-AO as part of the community

ROBO-AO


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ROBO-AO


ROBO-AO


ROBO-AO

ROBO-AOROBO-AO

ROBO-AO

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Robo-AO on the P60

Credit: Melinda Deramo

Laser guide star

Adaptive Optics System +Science Instruments

Robotic Software RoboticTelescope

(P60)

UV Laser

Commercial 12 W @ 10 kHz, λ=355nm

UV Laser

Commercial 12 W @ 10 kHz, λ=355nm

Laser drilling and scribing

(Nilsson et al., 2004)

Laser beam projector

• Compact projector• Optional periscope• Uplink jitter correction with AO loop• UV Class 1 w.r.t. aircraft; no human spotters• ~ 20x more intense than Solar UV

AO system and science cameras

Robo-AO’s Wavefront Sensors

• Shack-Hartmann HOWFS• 11 x 11 subapertures• QE = 72% (at 350 nm)• Pockels cell range-gate

• Adjustable 0-650m

• Image motion (tip/tilt) measured with one of the two science instruments

Robo-AO’s Wavefront Sensors

• Shack-Hartmann HOWFS• 11 x 11 subapertures• QE = 72% (at 350 nm)• Pockels cell range-gate

• Adjustable 0-650m

• Image motion (tip/tilt) measured with one of the two science instruments

Robo-AO – Wavefront reconstructor

• Lightweight, fast Linux/C++ software–Capable of >3kHz–Running at 1.2 kHz

• Uses disk harmonics modal reconstructor–Better SVD inverse conditioning than Zernikes–Zero slope at edge of DM (less saturated actuators)–Just as compact as Zernike polynomials

Robo-AO – Wavefront reconstructor

• Lightweight, fast Linux/C++ software–Capable of >3kHz–Running at 1.2 kHz

• Uses disk harmonics modal reconstructor–Better SVD inverse conditioning than Zernikes–Zero slope at edge of DM (less saturated actuators)–Just as compact as Zernike polynomials

Robo-AO – Wavefront correctors

MEMS deformable mirror–12 x 12 actuators–3.5 µm stroke–UV-NIR AR window

Piezo fast steering mirror- Up to 4” tip/tilt correction

(Bifano, 2011)

Robo-AO: AO Error Budget

H-Band Strehl predictions

At Zenith• Greater than 40% Strehl with mV = 19 T/T in median conditions• FWHM at H < 0.26” in even 75% worst seeing conditions

Visible science camera

• Andor iXonEM+ DU-888 • Electron Multiplying CCD• 44” x 44” square FoV• 0.043” pixels (Nyquist at λ = 620 nm)

• Full frame rate: 9 Hz• Sub frame rate: ~300 Hz

InGaAs engineering IR camera

• InGaAs – (Xenics: Xeva)+ Affordable, readily available- Noisy, small format

- 50e- read- 6000e-/s dark- 320x240 pixel format- Triple stage thermo-electrically cooled- 0.098 arc sec/pixel Nyquist at λ~1.35 um…- Up to 350 Hz readout Cameralink- (100 Hz with USB2.0)

Xeva-1.7-320

Near-IR camera (A. N. Ramaprakash)

Hawaii-2RG (HgCdTe)–2k by 2k format–0.057” pixels (Nyquist at λ = 830 nm)

–2’ field of view–Excellent noise – multiple

non-destructive reads–Flexible readout

• Staring• Fast readout of subregions• Multiple ROI for better T/T • “Guiding” while integrating

Robotic control software (Riddle)


• Fully robotic control system–Subsystems work as daemons–Supervisor controls scheduling, operations–Watchdog processes



• Programming intelligence is a challenge–Robots are only as smart as the people that make them!–Error control and exception handling



• Programming intelligence is a challenge–Robots are only as smart as the people that make them!–Error control and exception handling

• Safety system for equipment and staff–Laser safety a priority

Robo-AO is an excellent platform for student research

• Caltech graduate students– S. Tendulkar (dissertation) – hardware development + science– M. Kasliwal and T. Morton – on science planning team

• IUCAA undergraduates– Designing, building, testing electronics

• Summer undergraduates at Caltech (7 so far)– Developing software (motion control, web status monitoring, queue, scheduling,

communications, data reduction pipeline, …)

• Pomona College undergraduates building NGS only Robo-AO

Robo-AO has an ambitious future

Robo-AO is currently being commissioned on the P60

Initially a 1 month durationdemonstration of science this fall!(with hopefully more to follow)




Clone and deploy Robo-AO around the world–To 2-m IUCAA Girawali Observatory (A. N. R.)–Pomona College’s 1-m at Table Mountain, CA (P. Choi)–South Pole for mapping galactic Dark Matter (Dekany)




Clone and deploy Robo-AO around the world–To 2-m IUCAA Girawali Observatory (A. N. R.)–Pomona College’s 1-m at Table Mountain, CA (P. Choi)–South Pole for mapping galactic Dark Matter (Dekany)–Hopefully to a telescope near you!

Thank you!

This work is supported by the National Science Foundation under grants AST-0906060 and AST-0960343, as well as Robo-AO partner institutions, the California Institute of Technology

and the Inter-University Centre for Astronomy and Astrophysics.

Thank you to the Indo-US Science and Technology Forum for making this workshop possible.

Documents

Robo-AO: an autonomous laser adaptive optics and science system · 2011-09-02 · Demonstrate an autonomous, laser adaptive optics and visible/NIR science system on a 1.5-m ... on