Now I see it a little differently. To me, it gets more complicated when astronomers don't use light-travel time. Cas A exploded 10,000 years ago, but the light only reached Earth in 1680. What could be simpler? If you say we saw Cas A explode in 1680 that is fine, but to say it exploded in 1680 is misleading.

Some might say we cannot consider an event to have happened until we have seen it, but obviously as soon as we see it we know it has happened and if we have an idea of how long the light we see has been travelling for, then we have an idea how far in our past the event happened.