Our galaxy is an SBbc medium size and mass spiral type. It is only partially visible, since we are inside it; the plane of the disk and the thousands of stars it contains appear to us as a milky white stripe on the celestial vault, called the Milky Way. The Galaxy is composed of a central core, a bulge, a disk and a halo. In particular, the disc contains the spiral arms. The spiral nature of the Milky Way was confirmed through the study of the distribution of the HII regions, consisting mainly of bright nebulae of ionized hydrogen (HII) that form right inside the spiral arms. The spiral arms are regions of active formation of new stars, dominated by young stars, dust and gas.

In this conference paper, we present the development of radio astronomy in Hong Kong in 21 cm wavelength since 2006. We discuss the subtropical region with its usual cloudy condition in Hong Kong for launching radio astronomy. The MIT small radio telescope and Italy SPIDER radio telescope series were good starting points to create radio astronomy for a dense human populated region like Hong Kong. We present some interesting results with respect to these two types of radio telescopes. We also introduce the future possibility for the developing radio interferometry array in Hong Kong for research and teaching.

Cassiopeia A it’s an important object for radio astronomy, a supernova remnant located in Cassiopeia constellation with a flux of 2400 Jansky at 1420 MHz. For this article we used the SPIDER 300A radio telescope that, thanks to the 3 meter parabolic antenna with high precision WP-100 mount, high sensitivity H142-One receiver, and the advanced features of the RadioUniversePRO software, is able to detect Cassiopeia A. The radio telescope is connected to the remote control room by using the Radio over fiber kit for SPIDER radio telescope that removes the normal gain loss because of cable length and improve even more performances of the radio telescope.

The Sun is one of the most interesting radio sources in the sky and solar radio emission can be studied by using SPIDER radio telescopes. The Sun not only emits visible light but also other frequencies in the electromagnetic spectrum, in fact you can feel the Sun heat on our skin, expression of infrared radiation. In this article with step-by-step guide, by using a 3 meter diameter SPIDER 300A radio telescope, we see how to detect radio waves coming from the Sun and generate various results (like radio images and transits) by using the RadioUniversePRO control software. We perform automatic pointing and tracking on the Sun, detection and removal of eventual artificial signal and capture of results.