| Abstract | Period-luminosity relationships suitable for application to extragalactic Cepheids are given and applied to the results of recent work on M33. The Cepheid observations alone suggest that the true distance modulus of M33 is 24m.25 and that the extinction AV is 0m.45. The uncertainty in this distance modulus is probably about 0m.2 relative to the LMC. If a recent determination of the M33 modulus from red supergiant variables is included in the solution the best estimate of the true modulus is 24m.4 with AV = 0m.3. |
