An Improved Orbital Ephemeris for Cygnus X-1

C. Brocksopp, A. E. Tarasov, V. M. Lyuty +1

By accumulating all available radial velocity data and combining it with our own spectroscopy we present a new and improved ephemeris for Cygnus X-1 (V1357 Cygni/HDE226868). We ini…