LUCI1 and LUCI2 are a pair multi-mode, fully cryogenic near-infrared instruments installed at the Large Binoc- ular Telescope (LBT). The instruments provide imaging, long-slit and multi-object spectroscopy over a 4/ FoV in seeing-limited mode. Ground-layer AO (GLAO) correction for imaging and spectroscopy over the 4/ FoV is available using the ARGOS laser system, as well as diffraction-limited AO over a 30// FoV using the LBT first light AO (FLAO) system with natural guide stars. Internal flexure of the instrument is taken care of by passive and active flexure compensation. Image shifts in seeing-limited modes are compensated by a passive flexure con- trol algorithm using pre-defined look-up tables. For AO observations, passive compensation is replaced by active control. In the following, we present the details of the newly developed active flexure compensation algorithm for the LUCI instruments. We also describe some hardware modifications to the instruments and the results obtained with active flexure compensation.
The LUCI instruments are a pair of NIR imagers and multi-object spectrographs located at the front bent Gregorian foci of the Large Binocular Telescope (LBT). One of their special features is their diffraction-limited imaging and long-slit spectroscopic capability in combination with the LBT adaptive secondary mirrors. This allows to achieve a spatial resolution down to 60mas and a spectral resolution of up to 25000. Switching from seeing-limited to diffraction-limited observations changes several operational aspects due to features such as the non-common path aberration or the flexure of the instruments. They all require novel techniques to optimize the image quality and to maximize the scientific return. Non-common path aberration can be corrected via look-up tables. For active flexure compensation the night-sky emission is used. The commissioning of the instruments in diffraction-limited mode on sky is largely finished and the instruments have been handed over to the LBT in April 2018.
The following summarises changes in the scientific and technical operation of the Spanish-German astronomical center on Calar Alto which aim to maximise the scientific return. Most importantly, we introduce service observations which have the rationale to complete
whenever possible the most highly ranked scientific programmes, and to carry out the programme at the meteorological conditions which are best suited for it. We have started to monitor all instruments using specific calibration plans, and we carry out an optical engineering programme which consists of CO<sub>2</sub> cleaning of the telescope mirrors in 1--2 week intervals in order to maintain a high reflectivity and a low scattering at any time. Technical modifications of the 3.5m dome are discussed which now enable a fast and efficient ventilation of the dome before and during observations.
We report on the calibration and field test results obtained with the ESO/Meudon Adaptive Optics System, Adonis. This 7x7, 50cm subaperture system is now routinely in use at the ESO La Silla 3.6m telescope, offered to the astronomers together with two infrared cameras covering the 1-5 µm wavelength range. The calibration activity summarized here has investigated the field performances achieved so far with Natural Guide Stars (NGS) using the either the Reticon or the EBCCD wavefront sensors.