The ALHAMBRA-Survey is a project to gather the data necessary to sample a cosmologically significant fraction of the Universe with enough precision to follow the evolution of its content and properties with z , a kind of Cosmic Tomography .
It is defined as a large area , 4 \square ^ { \circ } , photometric survey with 20 contiguous , equal width , medium band filters covering from 3500 Å to 9700 Å , plus the standard JHK _ { s } near-infrared bands .
The photometric system in the optical was optimized to get ( for a fixed amount of total observing time ) the maximum number of objects with accurate classification and redshift and to be sensitive to relatively faint emission features in the spectrum .
We expect to be able to detect emission features down to EW = 35 Å , for S/N \approx 30 .

The observations will be carried out with the 3.5m telescope in Calar Alto ( Spain ) using the new wide field cameras in the optical ( LAICA ) and in the NIR ( OMEGA-2000 ) .
We intend to reach the limit AB = 25 mag ( for an unresolved object , S/N=5 ) in all the optical filters from the bluest to 8300 Å , and from 24.7 to 23.4 for the remainder .
The expected limit in the NIR is fixed at K _ { s } = 20 mag , H = 21 mag , J = 22 mag .

The homogeneous and contiguous spectral coverage will result in several hundred thousand objects with accurate SED identification and z-values .
The accuracy of the survey will allow us to study , among others , the large scale structure evolution with z , the identification of clusters of galaxies ( with membership assessment for a significant fraction of the galaxies ) , the identification of families of objects , and other detailed studies , without the need for any further follow-up .
Indeed , it will provide exciting targets for large telescopes , the GTC in particular .
Given its area and spectral coverage and its depth , apart from those main goals , the ALHAMBRA-Survey will also produce valuable data for galactic studies .