>>12
Look, I had thought that I was quite clear:
1. Invisible steller source.
2. Indications of gravity.
3. Indications of extreme gravity (radiation bursts).
4. Some accompanying gas shells from nova explosion.
All these things are about as close to "definitive proof" as you're going to get for being 6000 LY away. Not even the Hubble will be able to image a star collapsing to a invisible, point source ... even in real time. The collapse would produce such a flood of radiation that any actual image of shrinking (including lensing changes) would be wiped out in the glare.
The point is, we observed Supernova 1987A sufficiently:
http://en.wikipedia.org/wiki/SN_1987A
... to show that our suppositions so far were largely correct. The remnant left over from such explosions is a collapsed body ... either a neutron star or an actual collapsar -- a black holes. In SN1987A's case, there was a massive star, and now there's nothing detectable in the center due to the enshrouding gases still ejecting at high speeds. Once those clear a bit (decades? centuries?) we'll be able to see the tiny object (neutron star or black hole) at the center ... but the massive bulk of the star is gone.
If we're actually close enough to a supernova explosion to successfully image the collapse, then it's likely the Earth will be so damaged from the radiation waves that our civilization will end. The waves will not arrive all at once; largely the light will arrive first, some particles some time later, then the heavy particles years later. But our ozone will be gone and our atmosphere will be so assaulted by light radiation that we'd have to become Morlocks or something.
When the heavy particles arrive, years to decades later, a lot of death will occur at the surface, as each particle will arrive with the energy of a rifle bullet. Just imagine a rifle bullet of energy applied to a particle less than an atom. Each impact would destroy (ionize) a few cells wide and a LOT of cells deep, in our bodies. You may as well just consider us microwaved on "HIGH", since the arrival densities of these particles will cook us in short order. All surface creatures will die when the planet rotates to present their area to exposure. Those small or lucky enough to hide, may survive. The oceans will provide protection, too, so sea life will definitely survive. Whales and other air breathers will have to risk lethal exposures when their side of the planet is facing the supernova site.
Anyway.