Special Notice #313: HST COS observing CW Mon tonight and V405 Peg is next target

November 30, 2012: Further to AAVSO Alert Notice 471 (www.aavso.org/aavso-alert-notice-471) and AAVSO Special Notice #311 (www.aavso.org/aavso-special-notice-311),

HST COS is observing the dwarf nova CW Mon TONIGHT:

    CW Mon    30 November 2012 20:54:49 through 1 December 02:26:19 UT

Please give CW Mon top priority NOW through the HST observations and continue to follow it for at least a few days after the observations.
CW Mon is 16.8V at minimum and unknown at maximum.

Coordinates for CW Mon: R.A. 06 36 54.58  Dec +00 02 17.3 (2000.0)

The next HST COS target is the UG-type dwarf nova V405 Peg:

        V405 Peg    7 December 2012 02:31:20 through 07:50:03 UT

Please focus on V405 Peg (after CW Mon in priority today but top priority after the CW Mon HST observations are over). Remember that your observations will be crucial for the HST scheduling team to decide around December 6 whether to carry out the observations. V405 Peg is 17.9V at minimum and 13V at maximum.

Coordinates for V405 Peg: R.A. 23 09 49.14  Dec +21 35 17.2 (2000.0)

As instructed in AAVSO Alert Notice 471, for CCD observers, simultaneous photometry [shortly before, during, and after the HST observations] would be ideal. B filter would be best for a light curve, although for the magnitude estimates, a V measurement would be best. An uninterrupted light curve would be better than cycling between filters. These targets are most likely too faint for positive visual observations at minimum, but if possible they are
welcome, as are visual fainter-than observations fainter than magnitude 15.0.

Charts for both targets may be created using VSP (www.aavso.org/vsp).

Please report observations as soon as possible to the AAVSO International Database as CW MON and V405 PEG, respectively.

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: