"The supernova was observed 30 years ago."
Correct. I misspoke. (Or misstyped.)

'As for the ones you refer to, we've not "seen" them "
I as speaking metaphorically, but also correct.

"This is the first time (that I've heard of) where we have a visual event where a black hole could be found, and for which we have the gamma ray evidence to support black hole formation."
I missed that point listening to the radio.