Special Notice #339: V406 Vir (SDSS J123813.73-033932.9) HST/COS observations early tomorrow

February 28, 2013:  Further to AAVSO Alert Notice 471 (http://www.aavso.org/aavso-alert-notice-471) and AAVSO Special Notice #338 (http://www.aavso.org/aavso-special-notice-338), HST/COS is scheduled to observe V406 Vir (SDSS J123813.73-033932.9) tomorrow:

           V406 Vir 2013 March 1 08:37:30 through 14:04:33 UT

Please observe this novalike variable (V=17.1-18.0 at minimum) tonight through March 2 and report your observations to the AAVSO. The nearly full moon very close to this system makes observations a challenge, but please try to take a snapshot if at all possible!

The next HST/COS targets are the dwarf novae SDSS J103533.03+055158.4 and SDSS J143544.02+233638.7. The planned observing schedule is:

SDSS J103533.03+055158.4  2013 March 8 07:42:37 through 15:04:27 UT
SDSS J143544.02+233638.7  2013 March 9 08:35:01 through 13:40:17 UT

SDSS J103533.03+055158.4 is V=18.8 at minimum and SDSS J143544.02+233638.7 is V=18.2. Observations are crucial beginning now and continuing through one night after the HST observations. They will be especially important in the 2-3 nights before the HST observations, as about 24-36 hours before the planned observations the HST/COS scheduling team will make the final decision whether to observe each system.

As instructed in AAVSO Alert Notice 471, for CCD observers, simultaneous photometry [shortly before, during, and after the HST observations] would be ideal. For the magnitude estimates, a nightly V measurement from now through the HST observations and a day beyond would be best. If positive visual observations are possible, they are welcome, as are visual fainter-than  observations fainter than magnitude 15.0.

Coordinates (2000.0)
V406 Vir (SDSS J123813.73-033932.9)  R.A. 12 38 13.73   Dec. -03 39 32.8
SDSS J103533.03+055158.4  R.A. 10 35 33.03  Dec. +05 51 58.6
SDSS J143544.02+233638.7  R.A. 14 35 44.02  Dec. +23 36 38.7

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 names V406 VIR, SDSS J103533.03+055158.4, and SDSS J143544.02+233638.7, respectively. If an outburst is detected, please report observations immediately.  Many thanks!

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


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