SIMBAD references

We present mean spectra of three SU-UMa type dwarf novae and report orbital periods based on radial velocities taken near minimum light. For UV Per we find P_orb = 0.06489 ±0.00011 d (= 93.44 ±0.16 min); for V1504 Cygni, 0.06951 ±0.00005 (= 100.10 ±0.07 min), and for VY Aqr, 0.06309 ±0.00004 d (= 90.85 ±0.06 min). The period for VY Aqr is slightly shorter than the period determined by Augusteijn from velocities during outburst, and is more consistent with expectations based on the superhump period. For UV Per we also present timeseries photometry obtained on two nights. A weak modulation may be present at a period near, but formally distinct from, the orbital period. A magnitude sequence is presented.(c) Astronomical Society of the Pacific