This beautiful open star cluster is easily visible to the naked eye in clear winter nights. However, the delicate blue nebulae around the bright stars are hardly discernable from the glare that really big telescopes produce - big enough for observing this dim haze in the interstellar voids. So again, it's eventually up to the astrophotographers to capture those details that the human eye is hardly able to see...
The star cluster's distance is around 437 light years. Why should this be important? The Pleiades are a crucial beacon in the astronomical scale and at the edge of what hipparcos satellite was able to accurately measure. From this distance all the other scales we use to measure our universe up to the most distant galaxies are calibrated. This makes the Pleiades not only a lovely winter sky jewelry box, but also an important object for the professional astronomical community.