■ [unidentified] J1509-21: fading trend continues
The object keeps decaying with the reddening trend.
■ [IP][dwarf nova] HT Cam: high-speed photometry
HT Cam is an intermediate polar, occationally showing a quite short (<1 day) outburst, like dwarf novae. An outburst of the object was reported on 17 Apr. We performed high-speed photometry with a time-resolution of 1 sec. Preliminary light curves are shown in the above figure. The figure also includes our result during the last outburst in Feb. 2008. On 17 Apr, the object was almost at maximum of the outburst. We can see possible 200-300-s periodic modulations seem to be rapidly evolving. Compared with the light curve on 7 Feb. 2008, the light curve on 17 Apr. 2009 might exhibit shorter time-scale variations. On 18 Apr, longer time-scale modulations were apparently dominant. No signal of white-dwarf pluses (514 s) was detected in all light curves we obtained.
■ [unidentified] J1509-21: high-speed photometry
We performed high-speed photometry of this unidentified object on 18 Apr. The above light curve is an example of our 2-hour run. The time-resolution of the observation is 1 sec. We calculated the power spectrum using the light curve. No periodic variation was found. Short-term (2 sec - 100 sec) variations were weak. The light curve is apparently dominated by a white noise.