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IY UMa superoutburst: new data received Dear Colleagues, We have received new data sets from D. Starkey, J. Pietz (two nights), Tanabe-san at Okayama Sci. Univ. (two nights) in addition to regular data at Kyoto and Ouda. The most recent data sets from D. Starkey and J. Pietz clearly depict the phenomenon when superhump maxima passed the eclipse phases. The same phase (1 beat period before this conjunction) was precisely covered by observations by Tanabe-san. The light curve is very impressive. Further analysis is keenly in progress by Uemura-san. The object is still in superoutburst. More observations are strongly encouraged to completely follow the entire superoutburst! To those who have newly engaged in photometry of this dwarf nova, please keep the following instructions in mind: 1) always include the 10-th mag comparison star west to the variable (see CCD images on the VSNET website), 2) exposure times should be less than 60s (preferably 10-30s), 3) be careful that the comparison star is not saturated or close to saturation, and 4) adjust your PC clock to better than 1 sec, and prepare for rapid changes around eclipses. In contrast to usual eclipse observations, we need full phase coverage (i.e. also observe outside the eclipses). This is essential to follow the evolution of superhumps (and late superhumps at later stages). Continue observing as long as you can (several hours, or more if conditions allow), which enable to clearly demonstrate the beat phenomenon between superhumps and eclipses (orbital period). Everything looks fine up to now, and we congratulate all observers who have reported these exciting data! Regards, Taichi Kato
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