< p >我发现时间在澳大利亚西部的声明是基于南十字星座的位置有点投机。一些支持性的证据将会改善这个问题。< / p > < p >西澳大利亚英国殖民的历史,建立了南十字星多年后的最初两个定居点奥尔巴尼和珀斯。< / p > < p > < a href = " https://en.wikipedia.org/wiki/Albany%2C_Western_Australia " rel = " nofollow noreferrer " >奥尔巴尼< / >最初是建立在1826年作为一个军事哨所。< / p > < p > < a href = " https://en.wikipedia.org/wiki/Perth " rel = " nofollow noreferrer " >珀斯< / >于1829年建立,起初被称为天鹅河殖民地。它建立了殖民政府的所在地,最终政府当时的殖民地和仍然如此。< / p > < p > < a href = " https://en.wikipedia.org/wiki/Southern_Cross%2C_Western_Australia " rel = " nofollow noreferrer " >南十字星座< / >成立于1890年,61年成立后的珀斯。政府当局在珀斯就不会等待61年建立一个系统的时间在珀斯和其他殖民地。< / p > < p >行经度(经常)和时差格林威治子午线的这三个地方是:< / p > < p > <跨类= " math-container " > \开始{数组}{c c c | | | |}{位置}\线\文本,文本\{以东}, \text{Time from Greenwich}\\ \hline {Perth} & 115^o\ 51'\ 38" & 7h\ 43'\ 27" \\ \hline {Albany} & 117^o\ 52'\ 53" & 7h\ 51'\ 32" \\ \hline {Southern\ Cross} & 119^o\ 19'\ 40" & 7h\ 57'\ 19" \\ \hline \end{array} The times are based in the Earth rotating effectively 360° in 24 hours, or at a rate of 15° per hour.
For the colonial authorities in 1829, 7 hours 43 minutes and 27 seconds would have been close enough 8 hours from the Greenwich meridian to set the time for the colony to be 8 hours ahead of Greenwich. The fact that Southern Cross is only 2 minutes 41 seconds short of 8 hours time difference from Greenwich is a coincidence.
When the Sun is directly overhead in Perth the so called "true time" is 12h 16' 33".