Starfire Optical Range 3.5-m telescope adaptive optical system

Spinhirne, J. M.; Allen, Jeff G.; Ameer, George A.; Brown, James M.; Christou, Julian C.; Duncan, Terry S.; Eager, Robert J.; Ealey, Mark A.; Ellerbroek, Brent L.; Fugate, Robert Q.; Jones, G.W.; Kuhns, R. M.; Lee, Dong Hoon; Lowrey, W. H.; Oliker, Michael D.; Ruane, R. E.; Swindle, D.W.; Voas, Joshua K.; Wild, Walter J.; Wilson, Keith B.; Wynia, John L.

doi:10.1117/12.321689

Cited by 14 publications

(9 citation statements)

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“…5 In contrast, the AO system at the SOR 3.5m telescope uses 941 actuators operating at a 1500 Hz frame rate. 6 For the AO system at Mt. Wilson at V band (0.55 µm) the energy in the core, as approximated by the Strehl ratio, is about 9% for summer observing conditions, whereas the AO system at the SOR 3.5m telescope is capable of concentrating up to ~40% of the energy in the core.…”

Section: Adaptive Optics and High Resolution Spectroscopymentioning

confidence: 99%

Adaptive optics echelle spectrograph for radial velocity studies

Reynolds

Lloyd‐Hart

et al. 2003

SPIE Proceedings

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Radial velocity studies represent the most successful method to date for the detection of extrasolar planets. Although radial velocity (v r ) measurement precision of 3 m s -1 is routinely achieved in some programs, it is important to understand and minimize sources of experimental error. Furthermore, velocity variations resulting from astrophysical processes contribute to velocity errors, and must be removed if precision is to be further improved. The use of spectrographs with telescopes having high order adaptive optics (AO) systems offers the possibility of achieving near diffraction-limited very high spectral resolution at visible wavelengths on ground-based telescopes. The small stellar image diameters obtained with adaptively corrected systems allow high resolution without a large loss of light at the spectrograph entrance aperture. The Adaptively Corrected Echelle Spectrograph (ACES), designed at Steward Observatory for a spectral resolution R ~ 200,000, couples the telescope image to the instrument with an 8-10µm diameter near single-mode optical fiber. The shorter effective slit permits the placement of more echelle orders on the detector after cross dispersion, with a correspondingly greater wavelength coverage per exposure. This simultaneous high resolution and large wavelength coverage can be used to improve the precision of radial velocity studies by improving wavelength calibration, reducing dataset internal errors, and permitting better characterization and removal of effects intrinsic to the stars themselves.

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Section: Adaptive Optics and High Resolution Spectroscopymentioning

confidence: 99%

Adaptive optics echelle spectrograph for radial velocity studies

Reynolds

Lloyd‐Hart

et al. 2003

SPIE Proceedings

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“…The sodium LGS AO system shares a common optical path with the SOR's 3.5-m natural guidestar (NGS) AO system [11]; thus, some optical constraints exist. A block diagram of the AO system is shown in Fig.…”

Section: Sodium Lgs Adaptive Opticsmentioning

confidence: 99%

Characteristics of sodium guidestars created by the 50-watt FASOR and first closed-loop AO results at the Starfire Optical Range

et al. 2006

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A computer-automated cw sodium guidestar FASOR (Frequency Addition Source of Optical Radiation) producing a single frequency 589-nm beam with up to 50 W for mesospheric beacon generation has been integrated with the 3.5-m telescope at the Starfire Optical Range, Kirtland AFB, New Mexico. Radiance tests have produced a peak guidestar V 1 magnitude = 5.1 (~7000 photons/s/cm 2 at zenith) for 30 W of circularly polarized pump power in November 2005. Estimated theoretical maximum guidestar radiance is about 3 times greater than measured values indicating saturation due to atoms possibly becoming trapped in F' = 1 and/or atomic recoil. From sky tests over 3.5 years, we have tracked the annual variation of the sodium column density by measuring the return flux as a function of fasor power and determining the slope at zero power. The maximum occurs on October 30 and the minimum on May 30, with corresponding predicted returns of 8000 (V 1 = 4.8) and 3000 (V 1 = 5.8) ph/s/cm 2 with 50 W of fasor power and circular polarization. The effect of the Earth's magnetic field on the radiance of the sodium laser guidestar (LGS) from various azimuths and elevations has been measured. The peak return flux over our observatory occurs at [az=198°; el=+71°], compared with the direction of the magnetic field lines at [190°; +62°], and it can vary by a factor of 3 over the sky above el = 30°. First results for non-optimized sodium LGS adaptive optics (AO) closed-loop operation have been obtained using binary stars. Strehl ratios of 0.03 have been measured at 850 nm and a 0.14 arc second binary star has been resolved during first closed loop observations. Guidestar characteristics, including radiance, size, and Rayleigh backscatter, the sodium LGS wavefront sensor (WFS) AO system, and recent closed-loop results on binary stars are presented.

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“…The error rejection function is therefore given by: Error rejection function bandwidth is defined as the frequency Wb such that 0.7072 = S (e) 2 (5) Substituting gi = 1 -fo and defining x = 0.7072,…”

Section: First Order Filter Design For a Specified Bandwidth Or Gain mentioning

confidence: 99%

<title>Single-input/single-output analysis of latency and quadrant detector saturation in adaptive optical systems</title>

1999

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Feedback control theory offers several useful tools for analysis of adaptive optics systems. The basic tools of single-input-single-output analysis are applied to design first order and optimal filters for a specific loop bandwidth or gain margin as a function of latency and sample rate. Optimizing filter loop bandwidth as a function of temporal disturbance and noise statistics is addressed with respect to the internal model principle. Latency, due to camera readout and processing time, is shown to be the primary design driver for optimal AO system performance. The effects of wavefront sensor saturation are discussed and simulation and experimental results are presented.

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Starfire Optical Range 3.5-m telescope adaptive optical system

Cited by 14 publications

References 1 publication

Adaptive optics echelle spectrograph for radial velocity studies

Adaptive optics echelle spectrograph for radial velocity studies

Characteristics of sodium guidestars created by the 50-watt FASOR and first closed-loop AO results at the Starfire Optical Range

<title>Single-input/single-output analysis of latency and quadrant detector saturation in adaptive optical systems</title>

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