1·This annual event is called a heliacal rising.
这个一年一度的活动被称为“偕日升”。
2·They continually adjusted it to the heliacal rising of Sirius, ensuring that they never got too far off in their seasons.
他们不断地调整它以适应天狼星的偕日升，确保他们在自己的季节里不会偏离太远。
3·This administrative calendar existed alongside the earlier agricultural and religious calendar that depended on the heliacal rising of Sirius.
这个行政日历与早期依赖于天狼星偕日升的农业和宗教日历并存。
4·They concentrated attention, not on heliacal risings and Settings, not on the horizon, but on the pole star and on the circumpolar stars which never rise and never set.
他们关注的不是星辰偕日升降，也不是地平线附近的星辰，而是永不落下的北极星和拱极星。