International audience
Fin des années 1950, sous l'initiative de R.H. Dicke, la mesure télémétrique Terre-Lune fut initialement pensée pour tester la théorie de la Relativité Générale (RG) au travers de la variation de la constante gravitationnelle et du principe de Mach. Plus tard, K. Nordtvedt démontra qu'une telle expérience permettrait également de tester...
Optical system performances can be affected by local optical turbulence created by its surrounding environment (telescope dome, clean room, atmospheric surface layer). We present our new instrument INdoor TurbulENce SEnsor (INTENSE) dedicated to this local optical turbulence characterization. INTENSE consists of using several parallel laser...
Optical system performances can be affected by local optical turbulence created by its surrounding environment (telescope dome, clean room, or atmospheric layer). This paper follows a previous one introducing the INdoor TurbulENce SEnsor (INTENSE) instrument for optical turbulence characterization in a local area by exploitation of laser beam...
International audience
Since autumn 2015, the Observatoire de la Côte d'Azur and the J.L. Lagrange Laboratory have equipped the Calern Observatory with a new generation station of atmospheric turbulence measurement (CATS: Calern Atmospheric Turbulence Station). The CATS station is equipped with a set of complementary instruments for monitoring atmospheric turbulence...
CATS: turbulence measurement and forecasting
The future generation of extremely large telescopes will be certainly equipped with wide-field adaptive optics systems. All the components of such adaptive optics systems have to be precisely specified, and most of the technical specifications are related to atmospheric turbulence parameters, particularly the profile of the refractive index...
International audience
We present first results of a new instrument, the Generalized Differential Image Motion Monitor (GDIMM), aiming at monitoring parameters of the optical turbulence (seeing, isoplanatic angle, coherence time and outer scale). GDIMM is based on a small telescope equipped with a 3-holes mask at its entrance pupil. The seeing is measured by the...
International audience
International audience
International audience
The optical turbulence measurement and characterization has become an essential information for optical link (telecommunication, telemetry, time transfert, ...) and for high-angular resolution imagining in astron- omy. For example, it has an impact on the quality and on the bit error rate of optical communication signals and it decrease the...
International audience
The Generalised Differential Image Motion Monitor (GDIMM) was proposed a few years ago as a new generation instrument for turbulence monitoring. It measures integrated parameters of the optical turbulence, i.e the seeing, isoplanatic angle, scintillation index, coherence time and wavefront coherence outer scale. GDIMM is based on a fully...
The Profiler of Moon Limb is a recent instrument dedicated to the monitoring of optical turbulence profile of the atmosphere. Fluctuations of the Moon or the Sun limb allow to evaluate the index refraction structure constant C 2 n (h) and the wavefront coherence outer scale L 0 (h) as a function of the altitude h. The atmosphere is split into...
International audience
ABSTRACT The forecast for atmospheric and turbulence conditions above astronomical observatories is of interest to the astronomical community because it allows observations to be planned with maximum efficiency, a process called flexible scheduling. It can also be used to simulate long-term site testing to provide local information useful for...
International audience
International audience
International audience
International audience
Abstract We report on observations of the extended environment of the bright Be star γ -Cas performed using intensity interferometry measurements within its H α emission line. These observations were performed using a modified version of the I2C intensity interferometry instrument installed onto the 1.54 m MéO optical metrology telescope and a...
Intensity Interferometry offers an interesting path forward for astronomical interferometry at very long baselines and at short wavelengths, all leading to extremely high angular resolution. Single photon counting detectors (and associated correlator technology) has evolved to allow a sensitivity gain of two orders of magnitude since the...