From the most plain coronagraph to the most populated spectrograph: a suite of some new instruments for LBT D. Magrin* a , R. Ragazzoni a , M. Bergomi a,b , A. Brunelli a , M. Dima a , J. Farinato a , L. Marafatto a,b , V. Viotto a a INAF - Osservatorio Astronomico di Padova, Vicolo dell'Osservatorio 5, I-35122 Padova, Italy b Dipartimento di Fisica ed Astronomia, Università degli Studi di Padova, via Marzolo, 8 - I-35131 Padova, Italy ABSTRACT The Large Binocular Telescope is one of the most unusual 8 m class telescope and surely it has been inspirational to a number of novel concepts and innovations. We present here a couple of recently traced opto-mechanical designs to fit some niches in the parameters space of astrophysical usage. A coronagraph, as simple as possible, to take advantage of the LBT XAO ability dedicated to the ExoPlanets detection and a multiple very wide field spectrograph in which a large number of tiny cameras is foreseen, all with equal optical elements but for the pupil aberration corrector. Keywords: wide field astronomy, segmented optics, focal reducer, coronagraph, exoplanets, LBT. 1. INTRODUCTION A relevant amount of instruments are available or will be available in the next few years at the Large Binocular Telescope (LBT) [1, 2]: an optical spectrograph MODS [3], an infrared spectrograph LUCI [4], a high-resolution echelle spectrograph with polarimetric capability PEPSI [5], a wide field optical camera LBC [6], a near-infrared and visible interferometric imager LINC-NIRVANA [7] and a thermal infrared imager and nulling interferometer LBTI [8]. Moreover, the extreme adaptive optics module of LBT, First Light Adaptive Optics (FLAO) [9], which has been recently installed, is obtaining outstanding results in terms of performance and reliability [10]. Hopefully, the laser guide star and wavefront sensing facility ARGOS [11] will obtain even better results. In this framework, we propose a detailed study of a wide field spectrograph (diameter 1.5 degrees) and a preliminary design of a simple coronagraph, able to fulfill the still not covered astronomical cases. In particular, the spectrograph design is based on the crucial point of making mass production of small optical elements (typical size less than 30 mm), avoiding the problems related with the production, handling and alignment of huge optical elements (bigger than 1 m) typical of the nowadays wide field instrumentation. While on the collimator and camera side (and eventually the following spectroscopic part) this is obviously achieved, we speculated that the pupil correction can be achieved with a family of correctors whose amount of aberration introduced depends upon the way these are mounted together. Of course, the complication of such instrument will be shifted on the alignment phase because of the handling thousands of small lenses instead of few big monolithic ones. On the other side, the combination of FLAO pyramid based sensor, together with the high dynamic and spatial resolution Adaptive Secondary Mirror, is giving an excellent performance in terms of achieved resolution, with results in terms of Strehl Ratio (SR) never obtained before. In the IR domain, performance is routinely achieving SR>90% in K Band on bright stars and even the results in J Band are considerably remarkable with SR>60%.The high number of actuators of the adaptive secondary mirror can, in principle, give good corrections also in the visible wavelength and, in fact, results as good as SR>45% have been obtained even in R Band. Without coronographic techniques, contrast higher than 10 5 have been measured in K band (close to 10 5 in H Band), at a radial distance of 0.5 arcsec from a guide star of M V =6. These results have convinced us to start a preliminary study of a simple coronagraph infrared wavelength bands (extendable to visible bands), based on classical Lyot masks, able to increase the contrast of at least a factor 10, and, thanks to its simplicity, able to be commissioned to the telescope in a timescale of about a couple of years. This should guarantee to LBT very important role in the field of ExoPlanets detection and characterization. *demetrio.magrin@oapd.inaf.it; phone +39 049 8293540; fax +39 049 8759840; Ground-based and Airborne Instrumentation for Astronomy IV, edited by Ian S. McLean, Suzanne K. Ramsay, Hideki Takami, Proc. of SPIE Vol. 8446, 84463D · © 2012 SPIE · CCC code: 0277-786X/12/$18 · doi: 10.1117/12.926775 Proc. of SPIE Vol. 8446 84463D-1 Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/10/2015 Terms of Use: http://spiedl.org/terms