Alongside the opposition, this is one of the most prevalent aspects found in long-term marriages. Jung called it the conjunctio, meaning a type of union that happens when one person's feminine projection (anima), the Moon is merging with someone else's masculine projection (animus) the Sun.

       In more traditional views it is better if the man is the Sun and the woman is the Moon, but in this day and age, when women have their on careers and are no longer seeking out men only for their status and relationships are based of emotional (Moon), romantic (Venus) and sexual compatibility (Mars), it is actually better for the man to be the moon in this connection (if the woman's Moon is also engaged in the synastry) because he will feel emotionally bonded to her and will project the idea of wife (his Moon) on to her identity (her Sun).

       The Moon feels familiar, at ease and  safe when the Sun is expressing their true and authentic self.  The Moon person feels like the Sun is acting out what they feel internally and may project their inner self onto the Sun. The Sun feels validated and supported in being who they are by the Moon's unspoken reassurance and approval. Just by existing alongside the Sun, the Moon gives confidence and a secure identity to the Sun.

       It is considered that the Moon is more passive and just goes along with whatever the Sun wants. That is not true. It may be true in hard aspects where there is conflict and if one luminary is stronger because of a better placement it will want to dominate, but in the conjunction, even if one is stronger by placement, there is a merging of supportive (Moon) and creative (Sun) energy. There is still the possibility of a codependent dynamic forming (the Moon person should not neglect the development of their own Sun). That is one of the reasons why I said it is better that the Moon is the man, because men tend to have a more well developed Sun and do not get easily swept by the co-dependent dynamic.

       Example when the Sun in stronger. Sun in Aries/ Moon in Aries. The Sun is exalted in Aries but the Moon does not do so well in a sign ruled by Mars. The Sun's identity is pretty secure, the Sun feels comfortable with expressing their true self. The Moon may still feel very comfortable being with the Sun, but Aries Moon may not know how to show support (Aries is not the most supportive of signs). In this case, the fact that the Sun is stronger will compensate the Moon's weakness (the Sun has a very secure identity and will not need very much support and reassurance from the Moon). That is the benefit of the conjunction - they compensate what the other lacks.