July 19, 2013: In AAVSO Special Notice #364 (http://www.aavso.org/aavso-special-notice-364)
the variable 1RXS J213807.1+261958 (OT J213806.6+261957) was stated as being the northern of the pair. It is in fact the SOUTHERN of the pair, and is moving to the northeast.
The coordinates given in Special Notice #364 were correct and are repeated here for your convenience.
July 19, 2013: HST/COS is scheduled to observe the WZ Sge-type variable 1RXS J213807.1+261958 (= OT J213806.6+261957) next week. Observations are scheduled for:
1RXS J213807.1+261958 (OT J213806.6+261957)
2013 July 25 17:26:50 through 21:05:23 UT
The scheduling team will likely make their final decision early on July 24, and your observations will be essential now through July 26.