586. Using an Umbrella on Shabbos
In an introductory note to this chapter, the Kitzur Shulchan Aruch writes that most Jews are already familiar with the prohibited labors of Shabbos and that he is only addressing common situations with which people may not be familiar. Clearly, the laws of Shabbos constitute an area requiring much greater study than this email alone will allow. 80:81 Any partition or canopy that one may not put up on Shabbos, if it's already assembled, it may not be taken down. Dismantling a tent, the reciprocal of assembling one, is equally prohibited on Shabbos.
80:82 One may not carry an umbrella – which is a covering designed to protect people from sun or rain - because opening it forms a canopy. (The possibility of carrying it outside an eiruv is a secondary problem – Bi’ur Halacha 315:8 s.v. tefach.)