May one use a telescope attached to a tripod (via a cradle around the telescope that has a wedge which fits into a corresponding slot on the tripod and held there by tightening a screw.) on Shabbos? I know that one may not attach it to the tripod on Shabbos but can one set it up before Shabbos and move it out (within an eruv) on Shabbos or is this an example of a "Menora shel Chuliyos" a menorah of parts? If it does fall on Shabbos and come apart I don’t believe the scope would survive the fall. Are we still afraid that it may fall, come apart and that I would forget and put it together? There are no electrical components on the scope.
Shalom, Thank you for your question. There are two separate parts to it. Firstly, the use of a telescope on Shabbat, and secondly, the question of using things that are attached with screws. In the question of using a telescope, the Shulchan Aruch (Orach Haim 307,17) discusses whether one may use an "istrobol" on Shabbat. The Mishna Brurah (ibid 66) describes it as a vessel used to look at the stars. Even though there is an argument about whether it is permitted or not, the custom is be lenient (see the Mishna Brurah ibid 65). Therefore someone who wants to may use a telescope on Shabbat. In relation to the problem of it perhaps coming apart and having to be put back together, if the telescope is firmly screwed to the tripod before Shabbat there is no problem. Blessings.