#148 Halachos of a Chupah
A chupah, wedding canopy, should be tachas kipas hashomayim (literally under the sky), i.e., outdoors, since that is considered a sign of blessing. Ashkenazim are very particular to keep this minhag so as not to emulate chukos ha’goyim, the behavior of non-Jews, who hold their wedding ceremonies indoors in their places of worship The chupah should be held up by four poles, preferably not by human hands; the poles may be held by people, but should rest on the ground. If this is not possible, the chupah poles may be held up by people. There are poskim who specify that the chupah be attached to the tops of the poles, not to their sides, similar to the halachos of tzuras hapesach, a door frame, as described in Eiruvin. However, many poskim disagree with this requirement. Some stipulate that the chupah should extend a bit over the tops of the poles, and most chupos are indeed made in this fashion. There is a debate among poskim whether a chupah may be made from a paroches, the covering of an aron kodesh, but there is no clear consensus on this matter.