Observer Effect

The idea that observation of an object or phenomenon intrinsically creates a Celestial magic interaction due to the nature of consciousness. Once a conscious mind observes something, it becomes part of the Celestial reality's 'sphere of awareness' and therefore can be affected by Celestial magic, along with adjusting in Significance based on the action taken.
Here's where it gets weird- basically, so long as a change isn't observed, it doesn't strictly have to make sense to a conscious mind. Unobserved blue quanta is able to move more freely, not having to be bound by the rules/influences of Celestial quanta. This is most commonly applied to masking illusions- those that make one thing look like another. If one witnesses the magic during its cast (while the object transitions from appearing one way to another), it falls apart and the illusion fails to take. This is generally called a transition observation. An interesting conclusion to draw from this is that Celestial quanta is personalized to a degree- there exist instances in which one 'viewpoint' (soul) may be affected and not another.
Magic observed by nobody, not just the intended target (and not even the caster), can be functionally considered divested from the Celestial reality, giving it a few niche uses (much more so in beings like demons). This is a very difficult set of circumstances to create, as most areas have a patron god, ambient spirits, or other such diffused entities which may perceive this transition. Areas completely independent from observation are generally called voids, or Celestial vacuums.