We present new absolute trigonometric parallaxes and relative proper motions for nine Galactic Cepheid variable stars : \ell Car , \zeta Gem , \beta Dor , W Sgr , X Sgr , Y Sgr , FF Aql , T Vul , and RT Aur .
We obtain these results with astrometric data from Fine Guidance Sensor 1r , a white-light interferometer on Hubble Space Telescope .
We find absolute parallaxes in milliseconds of arc : \ell Car , 2.01 \pm 0.20 Â ; \zeta Gem , 2.78 \pm 0.18 Â ; \beta Dor , 3.14 \pm 0.16 Â ; W Sgr , 2.28 \pm 0.20 Â ; X Sgr , 3.00 \pm 0.18 Â ; Y Sgr , 2.13 \pm 0.29 Â ; FF Aql , 2.81 \pm 0.18 Â ; T Vul , 1.90 \pm 0.23 Â ; and RT Aur , 2.40 \pm 0.19 Â , an average \sigma _ { \pi } / \pi = 8 % .
Two stars ( FF Aql and W Sgr ) required the inclusion of binary astrometric perturbations , providing Cepheid mass estimates .
With these parallaxes we compute absolute magnitudes in V , I , K , and Wesenheit W _ { VI } bandpasses corrected for interstellar extinction and Lutz-Kelker-Hanson bias .
Adding our previous absolute magnitude determination for \delta Cep , we construct Period-Luminosity relations for ten Galactic Cepheids .

We compare our new Period-Luminosity relations with those adopted by several recent investigations , including the Freedman and Sandage H _ { 0 } projects .
Adopting our Period-Luminosity relationship would tend to increase the Sandage H _ { 0 } value , but leave the Freedman H _ { 0 } unchanged .
Comparing our Galactic Cepheid PLR with those derived from LMC Cepheids , we find the slopes for K and W _ { VI } identical in the two galaxies within their respective errors .
Our data lead to a W _ { VI } distance modulus for the Large Magellanic Cloud , m-M = 18.50 \pm 0.03 , uncorrected for any metallicity effects .
Applying recently derived metalllcity corrections yields a corrected LMC distance modulus of ( m-M ) _ { 0 } =18.40 \pm 0.05 .
Comparing our Period-Luminosity relationship to solar-metallicity Cepheids in NGC 4258 results in a distance modulus , 29.28 \pm 0.08 , which agrees with that derived from maser studies .