A Cosmic Chance Encounter
Messier 45, the Pleiades, is perhaps the most famous open star cluster in the night sky. Long-exposure photography reveals a secret: the stars are currently sailing through a ghost-like cloud of interstellar dust.
This is a reflection nebula. Unlike emission gas which glows by its own light, this dust simply mirrors the intense light of the nearby stars. The distinct "striations" or parallel lines seen in the nebulosity are caused by the interaction of the dust with the local galactic magnetic field.
Imaging Challenges
- Star Halos: Managing reflections from the extremely bright primary stars is a constant battle during processing.
- Subtle Dust: Pulling out the deep Merope and Maia nebulosity requires long integration to overcome noise.
- Framing: At 110 arcminutes, M45 is massive; capturing the outer "dust curtains" requires a wide field of view.
"Traveling at 40 kilometers per second, the Pleiades are passing through a dusty region of space by sheer coincidence. In a few million years, the stars will leave this cloud behind, and the iconic blue wisps we see today will vanish, leaving only the brilliant diamonds of the cluster in the dark."