Extremely rare outburst of BC UMa

Visual magnitude estimates by VSOLJ members

object         YYMMDD(UT)   mag  code
BC UMa         940428.479   130: Arm  (CCD, rough estimate)
BC UMa         940428.517   126  Ths  confirmatory observation

Observer's code:
  Arm: M. Iida (Nagano, Japan) 20-cm refl. ST-6
  Ths: S. Takahashi (Shiga, Japan) 60-cm refl. visual

  BC UMa  11h 52m 16.0s  +49deg 14' 41" (J2000.0)
  - suspected SU UMa-type dwarf nova with very outbursts.
  - photometric period P=0.063d has been proposed (Howell et al., PASP 102,758)
  - see Mukai et al. (MNRAS 245,385) for spectroscopic description.
    (also a finding chart)
  - possible link between WZ Sge-type stars has been proposed (Kato, PASJ
    submitted)

  Follow-up observations including high-speed photometry and spectroscopy
  (no good spectra have been obtained during outbursts) are urgently required.

Regards,
Taichi Kato