PKS 1424+240 is a BL-Lac blazar with unknown redshift detected at high-energy gamma rays by Fermi-LAT with a hard spectrum .
It was first detected at very-high-energy by VERITAS and latter confirmed by MAGIC .
Attempts to find limits on its redshift include three estimations by modeling gamma-ray observations , and one obtained by analyzing Ly _ { \beta } and Ly _ { \gamma } absorption lines observed in the far-UV spectra ( from HST/COS ) caused by absorbing gas along the line of sight .
They allowed to constrain the redshift range to 0.6 < z < 1.19 , which places PKS 1424+240 in the very interesting condition to be one of the few candidates to be the most distant blazars detected at very-high-energy gamma rays .

Redshift determination of BL-Lac objects are difficult to achieve .
We have found that redshift of blazars can be determined by its association to a galaxy group or cluster .
To explore this possibility for PKS 1424+240 , we have carried out spectroscopic measurements with the Gemini North telescope of galaxies in its field of view .
In this work we present the optical spectrum of PKS 1424+240 and show preliminary results of the blazar environment characterization .
Spectroscopic redshift using the optical spectrum of PKS 1424+240 could not be determined in this work .