真太阳时是什么
民用时钟使用时区内统一的标准时间，但太阳到达当地最高位置的时刻会随经度和日期变化。所谓真太阳时校正，尝试把钟表时间调整到更接近当地太阳运动所对应的时间。部分命理流派采用这种校正，另一些流派直接使用出生地的法定时间。
经度修正
一个时区通常以某条标准经线为基准。出生地位于标准经线以东或以西，会造成太阳时与钟表时的差异。粗略换算中，经度每差一度约对应四分钟，但实际使用前必须确认经度的正负方向和出生时采用的 UTC 偏移。
均时差
地球轨道和自转轴倾角使太阳日长度在一年中并不完全均匀。均时差用于描述平均太阳时和视太阳时之间随日期变化的差异。它不是固定值，因此只做经度修正仍不等于完整的真太阳时近似。
历史时区与夏令时
出生地当年的法定时区可能与今天不同，某些地区还使用过夏令时或临时调整。仅根据现代城市时区推算历史出生时间可能产生误差。本网站要求用户输入出生当时的 UTC 偏移，尚未自动查询完整历史时区数据库。
什么时候差异最明显
如果校正后的时间跨越传统时辰边界或日期边界，命盘可能发生较明显变化。若原始出生时间本身只精确到一两个小时，复杂校正并不能消除资料不确定性。应同时保留原始钟表时间和校正结果。
流派差异
是否使用真太阳时属于方法选择，不是所有传统系统的统一规定。严谨的报告应说明是否校正、采用的经度、UTC 偏移和近似公式，让读者能够复核。
What Is True Solar Time?
Civil clocks use one standard time across a time zone, but the moment when the Sun reaches its highest local position varies with longitude and date. True solar time correction attempts to adjust clock time toward local apparent solar movement. Some chart-reading schools use this correction, while others use the legal time recorded at the birthplace.
Longitude correction
A time zone normally uses a standard meridian. A birthplace east or west of that meridian creates a difference between solar time and clock time. In a rough conversion, one degree of longitude corresponds to about four minutes, but the longitude direction and UTC offset used at birth must be confirmed.
The equation of time
Earth’s orbit and axial tilt mean apparent solar days are not perfectly uniform throughout the year. The equation of time describes the date-dependent difference between mean solar time and apparent solar time. It is not a fixed value, so longitude correction alone is not a complete approximation of true solar time.
Historical time zones and daylight saving
The legal time zone at a birthplace may have differed from its current setting, and some regions used daylight saving or temporary adjustments. Applying a modern city time zone to a historical birth may create errors. This website asks the user for the UTC offset at birth and does not automatically query a complete historical time-zone database.
When the difference matters most
A correction may produce a noticeable chart difference if it crosses a traditional time or date boundary. If the original birth time is only known within one or two hours, a complex correction cannot remove that underlying uncertainty. Keep both the original clock time and the corrected result.
Differences between schools
Using true solar time is a methodological choice, not a universal rule across all traditional systems. A careful report should state whether correction was used and identify the longitude, UTC offset, and approximation method so that the result can be reviewed.