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We present spectroscopic and photometric observations of 17 dwarf-nova superoutbursts obtained by KOOLS-IFU mounted on the 3.8 m telescope Seimei at Okayama Observatory of Kyoto University and through VSNET collaboration. Our spectroscopic observations for six outbursts were performed within 1 d from their optical peak. 11 objects (TCP J00590972+3438357. ASASSN-19ado, TCP J06073081-0101501, ZTF20aavnpug, ASASSN-19ady, MASTER OT J061642.05+435617.9, TCP J20034647+1335125, ASASSN-20kv, ASASSN-20kw, MASTER OT J213908.79+161240.2, and ASASSN-20mf) were previously unknown systems, and our observations enabled quick classification of their transient type. These results illustrate that Seimei telescope has the capability to conduct quick follow-up observations of unknown transients. Our photometric observations yielded that 11 objects are WZ Sge-type dwarf novae and their candidates, and the other six objects are SU UMa-type dwarf novae and their candidates. The He II 4686AA~ emission line was clearly detected among ASASSN-19ado, TCP J06073081-0101501 and MASTER OT J213908.79+161240.2, whose association with a spiral arm structure in an accretion disk has been suggested in the previous studies. Our result suggests that a higher-inclination system shows a stronger emission line of He II 4686AA, as well as larger-amplitude early superhumps.
We report our photometric and spectroscopic follow-up observations of the superoutbursts of three dwarf novae (GWAC,180415A, GWAC,181017A and GWAC,181211A) identified independently by the Ground Wide-angle Cameras system, one of the ground-based inst
We report multi-wavelength monitoring observations of an M-dwarf flare star AD Leonis with Seimei Telescope (6150--7930 {AA}), SCAT (Spectroscopic Chuo-university Astronomical Telescope; 3700--7500 {AA}), NICER (Neutron Star Interior Composition Expl
Spectra of 76 known dwarf novae from the LAMOST survey were presented. Most of the objects were observed in quiescence, and about 16 systems have typical outburst spectra. 36 of these systems were observed by SDSS, and most of their spectra are simil
We present photometric and spectroscopic follow-up observations of short-period variables discovered in the OmegaWhite survey: a wide-field high-cadence g-band synoptic survey targeting the Galactic Plane. We have used fast photometry on the SAAO 1.0
We report observations of the flickering variability of the dwarf nova RX And in five bands (UBVRI) on two nights. On 25 October 2019 the brightness of the star was $Bapprox 13.9$ mag, the amplitude of the flickering was 0.47 mag, and we estimate for