\begin{table}%t1 \caption{\label{Tab1}The Cepheids studied listed with increasing period.} %\centerline {\small \begin{tabular}{lccc} \hline \hline \noalign{\smallskip} Cepheid & $P^{(a)}$ & $D_{{\rm 4896}}$ & $\Delta RV_{{\rm c}} [{\rm 4896}]$ \\ & [days] & [{\%}] & [\kms ] \\ \hline R TrA & $3.38925$ & 6 & $ 28.6 _{\pm 0.5 }$ \\ S Cru & $4.68976$ & 6 & $ 33.5 _{\pm 0.5 }$ \\ Y Sgr & $5.77338$ & 5 & $ 34.3 _{\pm 0.5 }$ \\ $\beta$ Dor & $9.84262$ & 10 & $ 31.7 _{\pm 0.5 }$ \\ $\zeta$ Gem & $10.14960$ & 14 & $ 25.5 _{\pm 0.5 }$ \\ RZ Vel & $20.40020$ & 4 & $ 47.6 _{\pm 0.5 }$ \\ $\ell$~Car & $35.55134$ & 13 & $ 32.8 _{\pm 0.5 }$ \\ RS Pup & $41.51500$ & 4 & $ 42.4 _{\pm 0.5 }$ \\ \hline \end{tabular}} \par $^{a}$ The corresponding Julian dates ($T_{{\rm o}}$) can be found in Paper~II. \end{table}