An ongoing action research on a workshop in astronomy for in-service primary teachers in Hong Kong, providing an experiential learning opportunity to connect astronomy phenomena in the new science curriculum with observation activities. The astronomy section is considered one of the most difficult parts with abstract concepts, especially for teachers who mostly lack a science education background. By the usage of various tools for day and night observations and planetarium, participants make logical connections to astronomy beyond the textbook. With the experiential learning cycle, both teaching and learning can benefit from observation activities to improve the workshop continuously, to understand and fulfil the needs of primary school teaching in the new standard of science education.