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Título del libro: 3rd Ao4elt Conference - Adaptive Optics For Extremely Large Telescopes
Título del capítulo: Stereo SCIDAR: Profiling atmospheric optical turbulence with improved altitude resolution

Autores UNAM:
REMY FERNAND AVILA FOUCAT;
Autores externos:

Idioma:
Inglés
Año de publicación:
2013
Palabras clave:

Atmospheric turbulence; Optical telescopes; Altitude range; Altitude resolution; Fast imaging; Impulse response functions; Optical turbulence; Optimisations; Response functions; Turbulent layer; Cameras


Resumen:

We report on the recent results of stereo SCIDAR from the Nordic Optical Telescope in La Palma. Stereo-SCIDAR is a new extension to the Generalised-SCIDAR method. We use two fast imaging cameras to record the pupil images of a double star pair on separate channels. We can then reconjugate the cameras to planes above the telescope. In Generalised-SCIDAR the cameras are conjugate below the ground allowing profiling of the full volume of atmospheric turbulence above the telescope. By conjugating to multiple altitudes above the telescope in step increments we increase the altitude resolution of SCIDAR and are able to build up a full profile at this resolution or even concentrate profiling to a pre-selected altitude range. This is because the impulse response function of SCIDAR is altitude dependent and so by conjugating close to a layer we are able to reduce the width of the response function and so increase the resolution. As we conjugate close to a turbulent layer the signal from that layer also reduces, and there will be a point where we become blind to any turbulence. A balance between these effects defines the resolution. This increased resolution could allow real-time profiles with ~100 m altitude resolution, which may be required for real-time optimisation of LTAO on the ELT.


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