The Spectral Energy Distribution (SED) of blazars consists of two components. The low-energy
bump is interpreted as synchrotron radiation from accelerated electrons, while the high-energy
one is produced via inverse Compton scattering of the electrons by lower-energy photons. In the
leptonic model interpretation, the latter comes either from the synchrotron radiation produced by
the same population of electrons (Synchrotron Self-Compton, SSC, scenario) or from an external
photon field. According to hadronic models, high-energy emission is due to processes involving the
protons in the source. The investigation of blazar SED is important to determine which theoretical
models are in action and to infer the parameters that drive the microphysics of the system.
Multiwavelength (MWL) long-term monitoring of blazars is key since the SED modelling over
time allows the study of the radiative processes during different states. The blazar 1ES 1959+650
represents an ideal laboratory for that, being bright at all the wavelengths and located at low redshift
(z= 0.047) allowing its detection in the TeV band. Also, it underwent some flaring episodes in
the past. A long-term MWL monitoring of 1ES 1959+650 is ongoing under the coordination of
the MAGIC collaboration. During the last years, the source is experiencing its lowest state ever
reached, mainly at very high energies. This contribution presents the MAGIC+MWL observations
of the last 3 years, and the preliminary study focusing on an SSC interpretation of the data.