Tired Light? Different Speed of Light? Nope.
Some brilliance –
However, SN1987A gives us a nice little test of light’s constant speed. The explosion of the star and the later illumination of the ring were two separate events, several months apart. Yet the first light from the ring reached us exactly when expected, after a delay only due to the time it took the ring to light up. If light really were slowing down, then the time required for the first light from the ring to get here would be greater than time required for the original light from the exploding star; and that would indicate that the ring is much farther from us than the star. They wouldn’t appear to be part of the same system.