立竿见影，原来古人这样测四时节气（字载匠心·惊艳时光的中国智慧）

Core Viewpoint - The article discusses the historical significance and scientific contributions of the ancient Chinese astronomical instrument, the gnomon, which reflects the pursuit of scientific exploration and the integration of human civilization with the cosmos [6][12]. Group 1: Measurement of Time - In ancient times, the Chinese viewed the night sky as a "heavenly clock," leading to the development of the gnomon for measuring time based on the sun's shadow [7]. - The gnomon consists of two parts: the "gnomon" (a vertical stick) and the "scale" (a horizontal base with markings) [7]. - The earliest known gnomon was discovered at the Shanxi Taosi site, dating back approximately 4,300 to 4,000 years [7][8]. Group 2: Calendar Development - The need for a unified time standard for coordinating activities led to the establishment of calendars based on astronomical observations [9]. - The gnomon was crucial for observing the sun's shadow changes, which provided data for creating calendars, including the 24 solar terms [9]. - The 24 solar terms were documented in the Han Dynasty, indicating a well-established system that integrated astronomy, agriculture, and social practices [9]. Group 3: Continuous Exploration - The gnomon was not only a time-measuring tool but also essential for determining geographical orientation and site selection for capitals [10]. - The peak of Chinese astronomy occurred during the Yuan Dynasty, where advancements in gnomon design significantly improved measurement accuracy [10]. - The construction of the Star Observatory in Dengfeng, led by Guo Shoujing, exemplified these advancements, featuring a large gnomon that enhanced observational precision [10][11]. Group 4: Historical Impact - The gnomon transcended mere measurement, symbolizing the legitimacy and sacred order of dynasties in ancient China [12]. - The term "guinance" originated from the gnomon, representing standards and principles, reflecting its cultural significance [12]. - Despite modern advancements in astronomy, the wisdom embodied in the gnomon continues to inspire contemporary exploration of the cosmos [13].