We present BV photometry of the Galactic globular cluster ( catalog NGC~6402 ) ( M14 ) , based on 65 V frames and 67 B frames , reaching two magnitudes below the turn-off level .
This represents , to the best of our knowledge , the deepest color-magnitude diagram ( CMD ) of ( catalog NGC~6402 ) available in the literature .
Statistical decontamination of field stars as well as differential reddening corrections are performed in order to derive a precise ridgeline and derive physical parameters of the cluster therefrom .

We discuss previous attempts to derive a reddening value for the cluster , and argue in favor of a value E ( \bv ) = 0.57 \pm 0.02 , which is significantly higher than indicated by either the or ( corrected according to ) interstellar dust maps .
Differential reddening across the face of the cluster , which we find to be present at the level of \Delta E ( \bv ) \approx 0.17 mag , is taken into account in our analysis .
We measure several metallicity indicators based on the position of the red giant branch ( RGB ) in the cluster CMD .
These give a metallicity of { [ Fe / H ] } = -1.38 \pm 0.07 in the scale and { [ Fe / H ] } = -1.28 \pm 0.08 in the new ( UVES ) scale .
We also provide measurements of other important photometric parameters for this cluster , including the position of the RGB luminosity function ‘ ‘ bump ’ ’ and the horizontal branch ( HB ) morphology .
We compare the ( catalog NGC~6402 ) ridgeline with the one for ( catalog NGC~5904 ( M5 ) ) derived by , and find evidence that ( catalog NGC~6402 ) and ( catalog M5 ) have approximately the same age , to within the uncertainties – although the possibility that M14 may be slighlty older can not be ruled out .