scholarly journals A near-infrared pyramid wavefront sensor for Keck adaptive optics: real-time controller

2018 ◽  
Author(s):  
Sylvain Cetre ◽  
Olivier Guyon ◽  
Charlotte Z. Bond ◽  
Mark R. Chun ◽  
Sean B. Goebel ◽  
...  
Keyword(s):  
Real Time ◽  
Adaptive Optics ◽  
Near Infrared ◽  
Wavefront Sensor

scholarly journals Simulation Study of a Low-Light-Level Wavefront Sensor Driving a Low-Order, Near-IR Adaptive Optics System

1994 ◽  
Vol 158 ◽  
pp. 308-310
Author(s):  
David W. Tyler ◽  
Gary C. Loos
Keyword(s):  
Adaptive Optics ◽  
System Performance ◽  
Near Infrared ◽  
Light Level ◽  
Wavefront Sensor ◽  
High Fidelity ◽  
Low Light ◽  
Near Ir ◽  
Adaptive Optics System ◽  
Low Order

Two high-fidelity computer simulations are used to study low-order adaptive optics systems operating in the near-infrared. We study obtainable system performance using very dim reference sources at three IR wavelengths.

Near-infrared pyramid wavefront sensor for Keck adaptive optics: opto-mechanical design

2018 ◽  
Author(s):  
Peter L. Wizinowich ◽  
Adam Vandenberg ◽  
Mojtaba Taheri ◽  
James K. Wallace ◽  
Mark R. Chun ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Mechanical Design ◽  
Wavefront Sensor

PYRAMIR: a near-infrared pyramid wavefront sensor for the Calar Alto adaptive optics system

2003 ◽  
Author(s):  
Joana B. Costa ◽  
Stefan Hippler ◽  
Markus Feldt ◽  
Simone Esposito ◽  
Roberto Ragazzoni ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Wavefront Sensor ◽  
Adaptive Optics System ◽  
Calar Alto

OPTICAL AND MECHANICAL DESIGN OF THE CHARA ARRAY ADAPTIVE OPTICS

2013 ◽  
Vol 02 (02) ◽  
pp. 1340007 ◽  
Author(s):  
X. CHE ◽  
L. STURMANN ◽  
J. D. MONNIER ◽  
T. A. TEN BRUMMELAAR ◽  
J. STURMANN ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Near Infrared ◽  
Angular Resolution ◽  
Mechanical Design ◽  
Wavefront Sensor ◽  
High Angular Resolution ◽  
Stellar Systems ◽  
Tilt Correction ◽  
Chara Array ◽  
Adaptive Optics System

The CHARA array is an optical/near infrared interferometer consisting of six 1-meter diameter telescopes with the longest baseline of 331 m. With high angular resolution, the CHARA array provides a unique and powerful way of studying nearby stellar systems. In 2011, the CHARA array was funded by NSF-ATI for an upgrade of adaptive optics systems to all six telescopes to improve the sensitivity by several magnitudes. The initial grant covers Phase I of the adaptive optics system, which includes an on-telescope Wavefront Sensor and fast tip/tilt correction. We are currently seeking funding for Phase II which will add fast deformable mirrors at the telescopes to close the loop. This paper will describe the design of the project, and show simulations of how much improvement the array will gain after the upgrade.

scholarly journals Real-time observation of tetrapyrrole binding to an engineered bacterial phytochrome

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yusaku Hontani ◽  
Mikhail Baloban ◽  
Francisco Velazquez Escobar ◽  
Swetta A. Jansen ◽  
Daria M. Shcherbakova ◽  
...  
Keyword(s):  
Real Time ◽  
Rational Design ◽  
Near Infrared ◽  
Fluorescent Proteins ◽  
Covalent Bond ◽  
Binding Pocket ◽  
Tissue Imaging ◽  
Covalent Attachment ◽  
Time Resolved

AbstractNear-infrared fluorescent proteins (NIR FPs) engineered from bacterial phytochromes are widely used for structural and functional deep-tissue imaging in vivo. To fluoresce, NIR FPs covalently bind a chromophore, such as biliverdin IXa tetrapyrrole. The efficiency of biliverdin binding directly affects the fluorescence properties, rendering understanding of its molecular mechanism of major importance. miRFP proteins constitute a family of bright monomeric NIR FPs that comprise a Per-ARNT-Sim (PAS) and cGMP-specific phosphodiesterases - Adenylyl cyclases - FhlA (GAF) domain. Here, we structurally analyze biliverdin binding to miRFPs in real time using time-resolved stimulated Raman spectroscopy and quantum mechanics/molecular mechanics (QM/MM) calculations. Biliverdin undergoes isomerization, localization to its binding pocket, and pyrrolenine nitrogen protonation in <1 min, followed by hydrogen bond rearrangement in ~2 min. The covalent attachment to a cysteine in the GAF domain was detected in 4.3 min and 19 min in miRFP670 and its C20A mutant, respectively. In miRFP670, a second C–S covalent bond formation to a cysteine in the PAS domain occurred in 14 min, providing a rigid tetrapyrrole structure with high brightness. Our findings provide insights for the rational design of NIR FPs and a novel method to assess cofactor binding to light-sensitive proteins.

scholarly journals The effect of stellar multiplicity on protoplanetary discs: a near-infrared survey of the Lupus star-forming region

2020 ◽  
Vol 501 (2) ◽  
pp. 2305-2315
Author(s):  
Alice Zurlo ◽  
Lucas A Cieza ◽  
Megan Ansdell ◽  
Valentin Christiaens ◽  
Sebastián Pérez ◽  
...  
Keyword(s):  
Adaptive Optics ◽  
Molecular Cloud ◽  
Near Infrared ◽  
Main Sequence Stars ◽  
Multiple Systems ◽  
Star Forming ◽  
Very Large Telescope ◽  
Pms Stars ◽  
First Time ◽  
Infrared Survey

ABSTRACT We present results from a near-infrared (NIR) adaptive optics (AO) survey of pre-main-sequence stars in the Lupus molecular cloud with NACO at the Very Large Telescope (VLT) to identify (sub)stellar companions down to ∼20-au separation and investigate the effects of multiplicity on circumstellar disc properties. We observe for the first time in the NIR with AO a total of 47 targets and complement our observations with archival data for another 58 objects previously observed with the same instrument. All 105 targets have millimetre Atacama Large Millimetre/sub-millimetre Array (ALMA) data available, which provide constraints on disc masses and sizes. We identify a total of 13 multiple systems, including 11 doubles and 2 triples. In agreement with previous studies, we find that the most massive (Mdust &gt; 50 M⊕) and largest (Rdust &gt; 70 au) discs are only seen around stars lacking visual companions (with separations of 20–4800 au) and that primaries tend to host more massive discs than secondaries. However, as recently shown in a very similar study of &gt;200 PMS stars in the Ophiuchus molecular cloud, the distributions of disc masses and sizes are similar for single and multiple systems for Mdust &lt; 50 M⊕ and radii Rdust &lt; 70 au. Such discs correspond to ∼80–90 per cent of the sample. This result can be seen in the combined sample of Lupus and Ophiuchus objects, which now includes more than 300 targets with ALMA imaging and NIR AO data, and implies that stellar companions with separations &gt;20 au mostly affect discs in the upper 10${{\ \rm per\ cent}}$ of the disc mass and size distributions.

Real-time tracking lysosomal pH changes under heatstroke and redox stress with a novel near-infrared emissive probe

Talanta ◽  
2021 ◽  
Vol 228 ◽  
pp. 122184
Author(s):  
Qingfeng Xia ◽  
Shumin Feng ◽  
Jiaxin Hong ◽  
Guoqiang Feng
Keyword(s):  
Real Time ◽  
Near Infrared ◽  
Redox Stress ◽  
Lysosomal Ph ◽  
Ph Changes ◽  
Real Time Tracking ◽  
Emissive Probe
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