The ornamental design for an open-top tent, as shown and described.
FIG. 1 is a side elevation view of an open-top tent, which illustrates my design;
FIG. 2 is a top perspective view thereof;
FIG. 3 is an additional top perspective view thereof;
FIG. 4 is an enlarged fragmentary bottom plan view of the central portion of the open-top tent;
FIG. 5 is an enlarged fragmentary top perspective view of the central portion of the open-top tent; and,
FIG. 6 is an enlarged fragmentary top perspective view of one of the six identical side corners thereof.
The dot-dashed lines around the outer edges in FIGS. 4-6 are boundary lines and form no part of the claimed design. The evenly spaced broken lines showing tent poles in FIGS. 1-6 form no part of the claimed design.