The ASTRI SST-2M prototype for the next generation of Cherenkov telescopes: Structure and Mirrors Rodolfo Canestrari *a , Enrico Cascone b , Paolo Conconi a , Mauro Fiorini c , Enrico Giro d , Nicola La Palombara c , Luigi Lessio d , Giovanni Pareschi a , Gabriele Rodeghiero d , Giorgia Sironi a , Luca Stringhetti c , Giorgio Toso c , Gino Tosti e for the ASTRI collaboration f and Francesco Martelli g , Giancarlo Parodi g , Pierfrancesco Rossettini h and Raffaele Tomelleri h a INAF-Osservatorio Astronomico di Brera – Via Bianchi, 46 23807 Merate (Lc) Italy b INAF-Osservatorio Astronomico di Capodimonte – Salita Moiaiello, 16 80131 Napoli (Na) Italy c INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica di Milano – Via Bassini, 15 20133 Milano d INAF-Osservatorio Astronomico di Padova – Vicolo Osservatorio, 5 35122 Padova (Pd) Italy e Università di Perugia – Via A. Pascoli 06123 Perugia (Pg) Italy f http://www.brera.inaf.it/astri/ g BCV progetti s.r.l. – Via Sant’Orsola, 1 20123 Milano (Mi) Italy h Tomelleri s.r.l. – Viale del lavoro, 12/a 37069 Villafranca (Ve) Italy ABSTRACT The next generation of Imaging Atmospheric Cherenkov Telescope will explore the uppermost end of the Very High Energy domain up to about few hundreds of TeV with unprecedented sensitivity, angular resolution and imaging quality. To this end, the Italian National Institute of Astrophysics (INAF) is currently developing a scientific and technological telescope prototype for the implementation of the Cherenkov Telescope Array (CTA) observatory. The Italian ASTRI program foresees the full design, development, installation and calibration of a Small Size 4-meter class Telescope, adopting an aplanatic, wide-field, double-reflection optical layout in a Schwarzschild-Couder configuration. In this paper we discuss about the technological solutions adopted for the telescope and for the mirrors. In particular we focus on the structural and electro-mechanical design of the telescope, now under fabrication. The results on the optical performance derived from mirror prototypes are here described, too. Keywords: Imaging Atmospheric Cherenkov Telescope, CTA, gamma-rays, wide field aplanatic telescope, lightweight mirrors, segmented optics, ASTRI 1. INTRODUCTION ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) [1] is a flagship project financed by the Italian Ministry of Education, University and Research and led by INAF. The ASTRI program is aimed to develop special technologies suitable for the ambitious CTA Observatory[2]. CTA will be implemented in two sites, in the northern in the southern hemispheres. It is composed by many tens of telescopes divided in three classes, in order to cover the energy range from a tens of GeV (Large Size Telescope, LST), to a tens of TeV (Medium Size Telescope, MST), and up to 100 TeV and beyond (Small Size Telescope, SST)[3]. The SST array will have 70 telescope units and it will be installed on the southern site. Within this framework, INAF is currently carrying on the development of an end-to-end prototype of SST in a dual- mirror configuration (SST-2M) to be tested under field conditions in Italy at the site of Serra La Nave[4], and scheduled to start data acquisition in late 2014. All the technological aspects concerning the development of the dual-mirror telescope prototype are covered within ASTRI, including the electro-mechanical mount for the telescope, primary and * rodolfo.canestrari@brera.inaf.it Optics for EUV, X-Ray, and Gamma-Ray Astronomy VI, edited by Stephen L. O'Dell, Giovanni Pareschi, Proc. of SPIE Vol. 8861, 886102 · © 2013 SPIE CCC code: 0277-786X/13/$18 · doi: 10.1117/12.2024379 Proc. of SPIE Vol. 8861 886102-1 Downloaded From: http://spiedigitallibrary.org/ on 11/12/2013 Terms of Use: http://spiedl.org/terms