Context : Binaries provide empirical key constraints for star formation theories , like the overall binary fraction , mass ratio distribution and the separation distribution .
They play a crucial role to calibrate the output of theoretical models , like absolute magnitudes , colors and effective temperature depending on mass , metallicity and age .

Aims : We present first results of our on-going high-resolution imaging survey of late type brown dwarfs .
The survey aims at resolving tight brown dwarf binary systems to better constrain the T dwarf binary fraction .
We intent to follow-up the individual binaries to determine orbital parameters .

Methods : Using NACO at the VLT we performed AO-assisted near-infrared observations of SDSS J2052-1609 .
High-spatial resolution images of the T1 dwarf were obtained in H and K _ { \mathrm { S } } filters .

Results : We resolved SDSS J2052-1609 into a binary system with a separation of 0.1009 \pm 0.001″ .
Archival data from HST/NICMOS taken one year previous to our observations proves the components to be co-moving .
Using the flux ratio between the components we infer J , H and K _ { \mathrm { S } } magnitudes for the resolved system .
From the near-IR colors we estimate spectral types of T1 ^ { + 1 } _ { - 4 } and T2.5 \pm 1 for component A and B , respectively .
A first estimate of the total system mass yields M _ { tot } \geq 78 M _ { Jup } , assuming a circular orbit .

Conclusions :