ORBITAL PERIODS FOR THE SU UMA-TYPE DWARF NOVAE UV PERSEI, VY AQUARII, AND V1504 CYGNI

We present mean spectra of three SU UMa-type dwarf novae and report or bital 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 V Y Aqr is slightly shorter than the period determined by Augusteijn fro m velocities during outburst, and is more consistent with expectations based on the superhump period. For UV Per we also present time-series photometry obtained on two nights. A weak modulation may be present a t a period near, but formally distinct from, the orbital period. A mag nitude sequence is presented.