Special Notice #364: 1RXS J213807.1+261958 (OT J213806.6+261957) HST obs next week

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.

When observing 1RXS J213807.1+261958, you will be imaging both the variable and its 15.1V companion (the combined magnitude is 14.8V). The astronomers know that and it is not a problem. It is important, however, to be aware of the companion in watching for an outburst of the variable.

PLEASE NOTE that the variable is the SOUTHERN of the pair. The coordinates given in VSX until July 16 referred to the southern star. (Note that this Special Notice originally reported the variable to be the northern of the pair.)

CORRECTED COORDINATES for 1RXS J213807.1+261958 (OT J213806.6+261957):
     R.A. 21 38 06.68   Dec. +26 19 56.6  (2000)

Charts may be created using the AAVSO Variable Star Plotter (http://www.aavso.org/vsp).

Please report observations as soon as possible to the AAVSO International Database using the name 1RXS J213807.1+261958 (the primary VSX name). If an outburst is detected, please report observations immediately. Many thanks!

Details of the HST/COS CV campaign may be found in AAVSO Alert Notice 471 (http://www.aavso.org/aavso-alert-notice-471). Related AAVSO Special Notices may be found via the Observing Campaigns page (http://www.aavso.org/observing-campaigns). AAVSO Special Notice #363 (http://www.aavso.org/aavso-special-notice-363) is the most recent one that pertains to the campaign.

This AAVSO Special Notice was compiled by Elizabeth O. Waagen.


Information on submitting observations to the AAVSO may be found at:


A Special Notice archive is available at the following URL:

Subscribing and Unsubscribing may be done at the following URL: