Some considerations about vibrations affecting optical telescopes tracking performance are here reported. They are based on experiences done in some very different case studies. Generally speaking the term noise comprises vibrations induced by the telescope to the pillar and vice versa. In some cases undesired mechanical connections between the telescope and the enclosure can produce the same effects namely a deprezation of the telescope tracking performance. Due to the always-different telescope/enclosure design the solution adopted to resolve vibration problems can also be substantially different.