Star
The Sun has an apparent magnitude of −26.7, but its absolute magnitude is only +4.83. Sirius, the brightest star in the night sky as seen from Earth, is approximately 23 times more luminous than the Sun, while Canopus, the second brightest star in the night sky with an absolute magnitude of −5.53, is approximately 14,000 times more luminous than the Sun. Despite Canopus being vastly more luminous than Sirius, however, Sirius appears brighter than Canopus. This is because Sirius is merely 8.6 light-years from the Earth, while Canopus is much farther away at a distance of 310 light-years.
NR Canis Majoris
NR Canis Majoris will eventually become the brightest star in the sky 2.6 million years from now to 3 million years from now, one of 4 different stars in Canis Major to hold that title (Alpha Canis Majoris, Beta Canis Majoris, and Epsilon Canis Majoris). During this period, NR Canis Majoris will be only 14 light years away and appear at -0.88 magnitude, about the same as Canopus today.