  Optical photometry is presented for the quadruple gravitational lens
PG1115+080. A preliminary reduction of data taken from November 1995 to June
1996 gives component ``C'' leading component ``B'' by 23.7+/-3.4 days and
components ``A1'' and ``A2'' by 9.4 days. A range of models has been fit to the
image positions, none of which gives an adequate fit. The best fitting and most
physically plausible of these, taking the lensing galaxy and the associated
group of galaxies to be singular isothermal spheres, gives a Hubble constant of
42 km/s/Mpc for Omega=1, with an observational uncertainty of 14%, as computed
from the B-C time delay measurement. Taking the lensing galaxy to have an
approximately E5 isothermal mass distribution yields H0=64 km/sec/Mpc while
taking the galaxy to be a point mass gives H0=84 km/sec/Mpc. The former gives a
particularly bad fit to the position of the lensing galaxy, while the latter is
inconsistent with measurements of nearby galaxy rotation curves. Constraints on
these and other possible models are expected to improve with planned HST
observations.
