  This paper presents new transit photometry from the Isaac Newton Telescope of
two transiting exoplanetary systems, XO-5 and WASP-82. In each case the new
transit light curve is more precise than any other of that system previously
published. The new data are analysed alongside previously-published photometry
and radial velocities, resulting in an improved orbital ephemeris and a refined
set of system parameters in each case. The observational baseline of XO-5 is
extended by very nearly four years, resulting in a determination of the orbital
period of XO-5b to a precision of just 50 ms. The mass and radius of XO-5b are
1.19$\pm$0.03 and 1.14$\pm$0.03 times those of Jupiter, respectively. The light
curve of WASP-82 is only the second published for this system. The planetary
mass is 1.25$\pm$0.05 $M_{\rm Jup}$, and the radius is 1.71$\pm$0.08 $M_{\rm
Jup}$.
