520 light-years is the apparent distance indicated by Hipparchus' astrometric results .
The ESA Hipparchus science satellite is no more, but
its astrometric data seems to indicate 520 light-years
with a certain degree of error.
Certainly, Beltegeuse is a lot closer to us than the giant star
that existed inside what is now the Crab Nebula.
And we know from Chinese records that the supernova
that happened in the Crab Nebula location was bright as the full-moon
for a little while.