We present seven nights ’ blue ( 4300–5000Å ) spectroscopy of the novalike variable star , V3885 Sgr .
The line spectrum shows a typical combination of broad absorption and emission in H \gamma and H \beta and He i , which is associated with the accretion disk .
We also observe anti-phased narrow emission , which we attribute to irradiation of the secondary star .
The He ii \lambda 4686 and N iii –C iii –C iv emission lines are devoid of structure and are most likely formed in an outflow .
We measure radial velocity shifts in the absorption and emission lines , from which we fit an orbital period of 4.97126 \pm 0.00036 h. From the velocity semi-amplitudes of the disk and companion star , we are able to constrain the binary mass ratio to q > 0.7 .

The phase-folded spectra provide dense coverage of the entire orbital cycle .
Doppler tomograms of the hydrogen and He i lines reveal spiral structure in the accretion disk and the irradiated donor star .
We believe this is the first unambiguous detection of spiral waves in a novalike variable .