當一顆行星將光束投射到兩顆行星之間的度數範圍內時，便稱為「介入」（intervening）。
例如，假設月亮位於獅子座10度，而火星位於獅子座25度，那麼這兩顆行星之間便相隔15度。如果木星恰好位於牡羊座12度，或位於牡羊座10度至25度之間的任何位置，那麼木星所發出的光束便介入了月亮與火星之間的空間。
同樣地，如果月亮位於獅子座10度，木星位於獅子座25度，而火星位於牡羊座12度，或牡羊座10度至25度之間的任何位置，也會形成相同的情況。
在這種情況下，我們便可以說，火星介入了月亮與木星之間。
It is labeled intervening whenever a planet throws a ray into the degrees between two planets. For instance, if the moon is at 10 Leo and Mars is at 25 Leo, then there are 15 degrees separating these two planets. And if Jupiter happens to be at 12 degrees of Aries, or anywhere between 10 and 25 degrees, then its beam is intervening into the space between the moon and Mars. This would also be the case if the moon was at 10 Leo, Jupiter was at 25 Leo, and Mars was in Aries at 12 degrees or anywhere between 10 and 25 degrees. In this case we might say that Mars is intervening between the moon and Jupiter.