On-sky results of the adaptive optics MACAO for the new IR-spectrograph CRIRES at VLT

The adaptive optics MACAO has been implemented in 6 focii of the VLT observatory, in three different flavors. We present in this paper the results obtained during the commissioning of the last of these units, MACAO-CRIRES. CRIRES is a high-resolution spectrograph, which efficiency will be improved by a factor two at least for point-sources observations with a NGS brighter than R=15. During the commissioning, Strehl exceeding 60% have been observed with fair seeing conditions, and a general description of the performance of this curvature adaptive optics system is done.Comment: SPIE conference 2006, Advances in adaptive optics, 12 pages, 11 figure

MIDI combines light from the VLTI: the start of 10 μm interferometry at ESO

International audienceWhen at the beginning of November 2002 the MIDI containers were opened up in Paranal and the team members together with ESO personnel started to assemble the instrument in the VLTI interferometric laboratory, nobody could be completely sure that their ambitious goal could actually be achieved: to bring together for the first time two beams of light from distant giant telescopes at the wavelength of 10 microns and obtaining stable, repeatable and accurate interference fringes. Although the instrument had been designed and built with the utmost care and all laboratory tests in Europe indicated that all specifications were met, going to the sky was another matter. The thermal infrared covers the wavelength range around the peak of the natural emission of a black body with a temperature about 300 K. This is close to the ambient temperature of the telescope mirrors and structure, of the two dozens of mirrors (in each arm) needed to bring the light into the tunnel and the interferometric lab, of all the mechanic structures, and of course of the sky. Therefore, at the wavelengths to which MIDI is sensitive, everything glows brightly! There is no distinction between day and night, and even the brightest stars are just tiny speckles of light in an overwhelmingly bright background. For this reason, previous attempts to perform interferometry in the thermal infrared had to find other ways to combine the light (for example, like Bester et al. (1990), in the style of radiointerferometers, thereby however sacrificing sensitivity), or never achieved a real routine operation. Even the ambitious efforts being carried out at the Keck Interferometer, in spite of having started earlier than at ESO, are so far still confronted with difficulties in this special area

MIDI combines light from the VLTI: the start of 10 μm interferometry at ESO

International audienceWhen at the beginning of November 2002 the MIDI containers were opened up in Paranal and the team members together with ESO personnel started to assemble the instrument in the VLTI interferometric laboratory, nobody could be completely sure that their ambitious goal could actually be achieved: to bring together for the first time two beams of light from distant giant telescopes at the wavelength of 10 microns and obtaining stable, repeatable and accurate interference fringes. Although the instrument had been designed and built with the utmost care and all laboratory tests in Europe indicated that all specifications were met, going to the sky was another matter. The thermal infrared covers the wavelength range around the peak of the natural emission of a black body with a temperature about 300 K. This is close to the ambient temperature of the telescope mirrors and structure, of the two dozens of mirrors (in each arm) needed to bring the light into the tunnel and the interferometric lab, of all the mechanic structures, and of course of the sky. Therefore, at the wavelengths to which MIDI is sensitive, everything glows brightly! There is no distinction between day and night, and even the brightest stars are just tiny speckles of light in an overwhelmingly bright background. For this reason, previous attempts to perform interferometry in the thermal infrared had to find other ways to combine the light (for example, like Bester et al. (1990), in the style of radiointerferometers, thereby however sacrificing sensitivity), or never achieved a real routine operation. Even the ambitious efforts being carried out at the Keck Interferometer, in spite of having started earlier than at ESO, are so far still confronted with difficulties in this special area

Preparing MIDI science operation at VLTI

International audienc

NAOS+CONICA at YEPUN: first VLT adaptive optics system sees first light

The Messenger. 2002. vol. 107.NAOS+CONICA (hereafter NACO) saw first light on November 25, 2001, at VLT UT4 (YEPUN). NACO partially compensates the effects of atmospheric turbulence (seeing) and provides diffraction- limited resolution for observing wavelengths from 1 to 5 μm, resulting in a gain in spatial resolution by a factor of 5 to 15 (diffraction limit of an 8-m-class telescope in K-band corresponds to 60 mas). This article gives an overview of the main characteristics and science drivers of NACO and briefly summarises the first results obtained during commissioning. Prospective users of NACO are kindly asked to cite [7] and [13] as a general reference to NACO in their scientific papers

NAOS+CONICA at YEPUN: first VLT adaptive optics system sees first light

The Messenger. 2002. vol. 107.NAOS+CONICA (hereafter NACO) saw first light on November 25, 2001, at VLT UT4 (YEPUN). NACO partially compensates the effects of atmospheric turbulence (seeing) and provides diffraction- limited resolution for observing wavelengths from 1 to 5 μm, resulting in a gain in spatial resolution by a factor of 5 to 15 (diffraction limit of an 8-m-class telescope in K-band corresponds to 60 mas). This article gives an overview of the main characteristics and science drivers of NACO and briefly summarises the first results obtained during commissioning. Prospective users of NACO are kindly asked to cite [7] and [13] as a general reference to NACO in their scientific papers