We present a correlation function analysis for the catalogue of photometric redshifts obtained from the Hubble Deep Field image by Fernandez-Soto et al. , 1998 .
By dividing the catalogue into redshift bins of width \Delta z = 0.4 we measured the angular correlation function w ( \theta ) as a function of redshift up to z \sim 4.8 .
From these measurements we derive the trend of the correlation length r _ { 0 } .
We find that r _ { 0 } ( z ) is roughly constant with look-back time up to z \simeq 2 , and then increases to higher values at z \mathrel { \hbox to 0.0 pt { \lower 3.0 pt \hbox { $ \sim$ } } \raise 2.0 pt \hbox { $ > $ } } 2.4 .
We estimate the values of r _ { 0 } , assuming \xi ( r,z ) = ( r / r _ { 0 } ( z ) ) ^ { - \gamma } , \gamma = 1.8 and different geometries .
For \Omega _ { 0 } = 1 we find r _ { 0 } ( z = 3 ) \simeq 7.00 \pm 4.87 h ^ { -1 } Mpc , in good agreement with the values obtained from analysis of the Lyman Break Galaxies .