We present deep VI photometry of stars in the globular cluster M5 ( NGC 5904 ) based on images taken with the Hubble Space Telescope .
The resulting color-magnitude diagram reaches below V \approx 27 mag , revealing the upper 2–3 magnitudes of the white dwarf cooling sequence , and main sequence stars eight magnitudes and more below the turn-off .
We fit the main sequence to subdwarfs of known parallax to obtain a true distance modulus of ( m - M ) _ { 0 } = 14.45 \pm 0.11 mag .
A second distance estimate based on fitting the cluster white dwarf sequence to field white dwarfs with known parallax yielded ( m - M ) _ { 0 } = 14.67 \pm 0.18 mag .
We discuss the nature of the difference between the two distance estimates and suggest approaches for reducing the uncertainty in white dwarf fitting estimates for future studies .
We couple our distance estimates with extensive photometry of the cluster ’ s RR Lyrae variables to provide a calibration of the RR Lyrae absolute magnitude yielding M _ { V } ( RR ) = 0.42 \pm 0.10 mag at [ Fe/H ] = –1.11 dex .
We provide another luminosity calibration in the form of reddening-free Wasenheit functions .
Comparison of our calibrations with predictions based on recent models combining stellar evolution and pulsation theories shows encouraging agreement , and the existing differences may provide useful feedback to the models .