As Ironboundtome noted, the errata states that Wizard's Communion must have a Duration of Sun to apply to rituals.
It has been proposed to follow what I understand is a relatively common house rule and ignore that errata, allowing Momentary Duration Wizard's Communion spells to work on rituals. I don't feel too strongly one way or another on this one and am happy to follow whatever the troupe would prefer. We've heard from some already. Any other thoughts?