OT_J211737.7+210736 = PNV J21173768+2107359 http://www.cbat.eps.harvard.edu/unconf/followups/J21173768+2107359.html This is most likely a dwarf nova (less likely a WZ Sge-type). There is a 22-mag object in SDSS. Time-resolved photometry is encouraged. (And the constellation is not "Vul")