Context : The most primitive metal-poor stars are important for studying the conditions of the early galaxy and are also relevant to big bang nucleosynthesis .

Aims : Our objective is to find the brightest ( V < 14 ) most metal-poor stars .

Methods : Candidates were selected using a new method , which is based on the mismatch between spectral types derived from colors and observed spectral types .
They were observed first at low resolution with EFOSC2 at the NTT to obtain an initial set of stellar parameters .
The most promising candidate , 2MASS~J18082002 $ - $ 5104378 ( V = 11.9 ) , was observed at high resolution ( R = 50 000 ) with UVES at the VLT , and a standard abundance analysis was performed .

Results : We found that 2MASS~J18082002 $ - $ 5104378 is an ultra metal-poor star with stellar parameters T _ { eff } = 5440 K , log g = 3.0 dex , v _ { t } = 1.5 km s ^ { -1 } , [ Fe/H ] = - 4.1 dex .
The star has [ C/Fe ] < +0.9 in a 1D analysis , or [ C/Fe ] \lesssim +0.5 if 3D effects are considered ; its abundance pattern is typical of normal ( non-CEMP ) ultra metal-poor stars .
Interestingly , the star has a binary companion .

Conclusions : 2MASS~J1808 $ - $ 5104 is the brightest ( V = 11.9 ) metal-poor star of its category , and it could be studied further with even higher S/N spectroscopy to determine additional chemical abundances , thus providing important constraints to the early chemical evolution of our Galaxy .