Hydrogen is the most abundant baryonic matter in the universe, with most of it existing in the form of hydrogen atoms. The hyperfine line of neutral hydrogen atoms at 21cm wavelength is a strong radio source in the sky, making it a tool to probe the distribution of cosmic baryonic matter. In this paper, we introduce the experiment of galactic neutral hydrogen line observation conducted on the 3.2m radio telescope at Sun Yat-sen University (SYSU). The dynamic spectrum is achieved from the time-domain electromagnetic signals. The signal-to-noise ratio is increased by binning the timesteps and the spectra channels in the experiment. We also introduce the observation modes of radio telescopes, and achieve automatic sky survey on the 3.2m SYSU radio telescope. Sky map of neutral hydrogen distribution in our galaxy is generated in an elective experiment. Based on the sky map, the distance between the sun and the galactic center is estimated, and the galactic rotation curve is obtained based on the redshift of the lines. This paper, combined with the previous experiment on the temporal variation of solar radio flux introduced in the first paper of this series, provide references for practical radio astronomy teaching.

With the development of astronomical observation equipment and the expansion of astronomical education in China, how to conduct practical teaching in astronomy has become a challenge for astronomy departments and physics departments with astronomy majors in colleges and universities, To adapt students to the rapid development of national major scientific installations, the School of Physics and Astronomy at Sun Yat-sen University (SYSU) completed the construction of a 3. 2-meter teaching radio telescope in 2021. Through three years of exploration in the course of “Astronomical Observation Practice”, the goal of helping students understand the structure and principles of radio telescopes, as well as the basic processes of astronomical observation, has been achieved, At the same time, we realize that this experimental platform can help students learn basic physical concepts such as spectral line broadening, error analysis and control, and time-frequency analysis of signals in practice. Students need to apply multidisciplinary knowledge to complete experiments, making it suit.able to open to general physics and engineering majors. This special topic is prepared in two parts to introduce the experiments on SYSU 3. 2-meter radio telescope, including telescope pointing control, generation of standard astronomical data, and specific time-domain and frequency-domain astronomical observation experiments, that is, experiment of solar radio flux intensity time-domain variation and the observation experiment of neutral hydrogen spectral lines. They are noted as a reference for us and other schools to carry out practical astronomy teaching, and for the radio telescope to serve as a platform for elective experiments in university physics.

This is the first part of the special topic, in which the basic parameters of the telescope as well as the design of student's experiments are introduced, It also has specific contents of two experiments that make the telescope functional for astronomical observations, i.e., astronomical source tracking and data file generation, The sun is an astronomical source with strong radio emission, Based on an example, we introduce the experiment of temporal variations of solar radio emissions.