Publications (23)
First light with HiPERCAM on the GTC
Vikram Dhillon, Simon Dixon, Trevor Gamble +20
HiPERCAM is a quintuple-beam imager that saw first light on the 4.2m William Herschel Telescope (WHT) in October 2017 and on the 10.4m Gran Telescopio Canarias (GTC) in February 20…
Extreme water wave profile recovery from pressure measurements at the seabed
Didier Clamond, David Henry
The aim of this note is to examine the efficacy of a recently developed approach to the recovery of nonlinear water waves from pressure measurements at the seabed, by applying it t…
Space-quality data from balloon-borne telescopes: the High Altitude Lensing Observatory (HALO)
Jason Rhodes, Benjamin Dobke, Jeffrey Booth +36
We present a method for attaining sub-arcsecond pointing stability during sub- orbital balloon flights, as designed for in the High Altitude Lensing Observatory (HALO) concept. The…
Curved detectors for wide field imaging systems: impact on tolerance analysis
Eduard Muslimov, Emmanuel Hugot, Simona Lombardo +7
In the present paper we consider quantitative estimation of the tolerances widening in optical systems with curved detectors. The gain in image quality allows to loosen the margins…
Characterisation of the Intel RealSense D415 Stereo Depth Camera for Motion-Corrected CT Perfusion Imaging
Mahdieh Dashtbani Moghari, Philip Noonan, David Henry +5
Even for short protocols (<1 min), head movement can compromise accurate haemodynamic modelling of cerebral CT perfusion (CTP) imaging in acute stroke. Frame-to-frame registration…
Higher-order integrable models for oceanic internal wave-current interactions
David Henry, Rossen I. Ivanov, Zisis N. Sakellaris
In this paper we derive a higher-order KdV equation (HKdV) as a model to describe the unidirectional propagation of waves on an internal interface separating two fluid layers of va…
ERIS: revitalising an adaptive optics instrument for the VLT
Richard Davies, Simone Esposito, Hans Martin Schmid +63
ERIS is an instrument that will both extend and enhance the fundamental diffraction limited imaging and spectroscopy capability for the VLT. It will replace two instruments that ar…
Instability of equatorial water waves with an underlying current
François Genoud, David Henry
In this paper we use the short-wavelength instability approach to derive an instability threshold for exact trapped equatorial waves propagating eastwards in the presence of an und…
One-dimensional weakly nonlinear model equations for Rossby waves
David Henry, Rossen Ivanov
In this study we explore several possibilities for modelling weakly nonlinear Rossby waves in fluid of constant depth, which propagate predominantly in one direction. The model equ…
On the existence of steady periodic capillary-gravity stratified water waves
David Henry, Bogdan-Vasile Matioc
We prove the existence of small steady periodic capillary-gravity water waves for general stratified flows, where we allow for stagnation points in the flow. We establish the exist…
Analysis of on-sky MOAO performance of CANARY using natural guide stars
Fabrice Vidal, Eric Gendron, Gerard Rousset +13
The first on-sky results obtained by CANARY, the Multi-Object Adaptive Optics (MOAO) demonstrator, are analysed. The data were recorded at the William Herschel Telescope, at the en…
On the persistence properties of the cross-coupled Camassa-Holm system
David Henry, Darryl D. Holm, Rossen I. Ivanov
In this paper we examine the evolution of solutions, that initially have compact support, of a recently-derived system of cross-coupled Camassa-Holm equations. The analytical metho…
Rotational flow underlying coupled surface and internal waves. I: Eulerian perspective
David Henry, Rossen I. Ivanov, Zisis N. Sakellaris
In this paper we examine the flow generated by coupled surface and internal small-amplitude water waves in a two-fluid layer model, where we take the upper layer to be rotational (…
The Visible and Infrared Survey Telescope for Astronomy (VISTA): Design, Technical Overview and Performance
Will Sutherland, Jim Emerson, Gavin Dalton +19
The Visible and Infrared Survey Telescope for Astronomy (VISTA) is the 4-metre wide-field survey telescope at ESO's Paranal Observatory, equipped with the world's largest near-infr…
Curved detectors developments and characterization: application to astronomical instruments
Simona Lombardo, Thibault Behaghel, Bertrand Chambion +8
Many astronomical optical systems have the disadvantage of generating curved focal planes requiring flattening optical elements to project the corrected image on flat detectors. Th…
High-contrast spectroscopy with the new VLT/ERIS instrument: Molecular maps and radial velocity of the gas giant AF Lep b
Jean Hayoz, Markus Johannes Bonse, Felix Dannert +66
The Enhanced Resolution Imager and Spectrograph (ERIS) is the new Adaptive-Optics (AO) assisted Infrared instrument at the Very Large Telescope (VLT). Its refurbished Integral Fiel…
Mean flow velocities and mass transport for Equatorially-trapped water waves with an underlying current
David Henry, Silvia Sastre-Gomez
In this paper we present an analysis of the mean flow velocities, and related mass transport, which are induced by certain Equatorially-trapped water waves. In particular, we exami…
Flow kinematics for equatorial coupled surface and internal waves
David Henry, Rossen Ivanov, Gabriele Villari
We study the propagation of coupled surface and internal equatorial internal waves. A model of two vertically stratified fluid layers with different constant densities is employed.…
Flexible focal plane arrays for UVOIR wide field instrumentation
Emmanuel Hugot, Wilfried Jahn, Bertrand Chambion +7
LAM and CEA-LETI are developing the technology of deformable detectors, for UV, VIS or NIR applications. Such breakthrough devices will be a revolution for future wide field imager…
Steady periodic water waves bifurcating for fixed-depth rotational flows with discontinuous vorticity
David Henry, Silvia Sastre-Gomez
In this article we apply local bifurcation theory to prove the existence of small-amplitude steady periodic water waves, which propagate over a flat bed with a specified fixed mean…
Two-component equations modelling water waves with constant vorticity
Joachim Escher, David Henry, Boris Kolev +1
In this paper we derive a two-component system of nonlinear equations which model two-dimensional shallow water waves with constant vorticity. Then we prove well-posedness of this…
Combining freeform optics and curved detectors for wide field imaging: a polynomial approach over squared aperture
Eduard Muslimov, Emmanuel Hugot, Wilfried Jahn +5
In the recent years a significant progress was achieved in the field of design and fabrication of optical systems based on freeform optical surfaces. They provide a possibility to…
Recovery of steady rotational wave profiles from pressure measurements at the bed
Didier Clamond, Joris Labarbe, David Henry
We derive equations relating the pressure at a flat seabed and the free-surface profile for steady gravity waves with constant vorticity. The resulting set of nonlinear equations e…