The purpose of this work is to obtain the curve of rotation of the Milky Way, to map the spiral structure of the Galaxy itself and to determine the integral mass; all this is done through the study of the galactic hydrogen concentration.
We used the radio telescope Salsa Onsala "Vale", a device with the diameter of 2.3 m built by the Onsala Space Observatory at the Chalmers University of Technology in Sweden.
The data which were used refer to several observations done between December 22nd 2011 and January 6th 2012. For the elaboration of those data, which were the spectrum of the radiation, the software SalsaJ was used.
The result of this study confirms that the matter velocity, far away from the galactic center, does not decrease, but remains the same.
The distribution of the hydrogen is not uniform: it is concentrated in filamentary structures which are considered an evidence of the presence of a spiral structure.