The recent discovery that the star Tr 27-28 is of spectral type WC 9 allows the determination of the visual absolute magnitude of a single WC 9-type star based on open cluster membership: Mv = —5.3 ± ...

Stars come in all colors and sizes. But our eyes limit us to seeing very few of those colors. And the range of apparent magnitudes of stars we can see with our naked eye is also rather limited.

If someone asks you, “How bright is that star?” and your answer is “Pretty bright,” that isn’t very useful. And, of course, it’s worthless for any type of comparative research. So for centuries, ...