Mechanical design considerations for a 3m class fast pointing telescope

A number of scientific observations take advantage of the use of robotic, fast pointing telescopes; in particular, fast reacting small telescopes were especially useful for gamma ray burst follow-up which now require better performances and greater telescope size. However, increasing telescope size could imply some limitations in terms of operability and technological solutions. In order to select the best telescope configuration it is necessary to take into account mechanical set up, pointing strategy, wind effects and the resulting effective costs. This paper will investigate and compare the characteristics of traditional alt-az and alt-alt telescope configurations considering also an innovative alt-alt set up to be developed as an alternative to the mainstream layout of present medium class telescopes. In the alt-alt case the system exploits the heritage of larger telescope projects like LBT, coupled with a more traditional fork mounted to match the alt-alt kinematics, so obtaining a more stable machine and minimizing the blind spot limitation.