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高中地理上册“九月星空图”下面有这样的叙述:适用于9月1日21时,9月15日20时,9月30日19时。为何日期后推15天,观察星空的时刻却要提前一个小时?在此我们可以用太阳日与恒星日的关系来解释一下。所谓太阳日,是指太阳连续两次经过上中天的时间间隔,时间为24小时,是我们日常生活中的计时单位。由于地球自转的同时还在绕日公转,因此,地球在一个太阳日内自转了360°59′。恒星日,是指天空某一恒星连续两次经过上中天的时间间隔,是地球自转的真正周期。时间为23时56分4秒,比太阳日短了3分56秒;对于恒性日我们可
The geography book “September’s sky map” contains the following narrative: It applies to 21 September 1st September, 20 September 15th, and 19th September 30th. Why is the date pushed 15 days later, and the time to observe the stars is one hour ahead? Here we can use the relationship between the solar day and the star day to explain. The so-called solar day refers to the time interval of 24 hours for the sun to pass twice through the sky, which is the unit of time in our daily life. As the earth rotates around the clock, it also orbits the sun. Therefore, the earth rotates 360°59’ in one solar day. Stellar day refers to the time interval in which a certain star of the sky passes through the sky twice and is the real cycle of the earth’s rotation. The time is 23:56:4, which is 3 minutes 56 seconds shorter than the day of the sun. For the day of constant nature we can