Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025
Definition
Dreyer is an observational astronomer known for cataloging nebulae and star clusters. His work is pivotal in understanding the distribution of gas and dust in space.
5 Must Know Facts For Your Next Test
Dreyer compiled the New General Catalogue (NGC) which contains over 7,000 objects including nebulae and star clusters.
The NGC is essential for identifying various interstellar medium components such as emission nebulae and dark nebulae.
Dreyer's catalog was later expanded into the Index Catalogue (IC), adding more objects and corrections to the original NGC.
His work provided a foundation for future astronomical surveys and studies of the interstellar medium.
Dreyer's contributions are crucial for understanding how gas and dust are distributed between stars.
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Related terms
Emission Nebula: A cloud of ionized gas emitting light of various colors, often associated with regions of star formation.
Dark Nebula: A dense cloud of gas and dust that blocks light from objects behind it, making it appear dark against the background.
Star Cluster: A group of stars bound together by gravity, often found within or near regions rich in interstellar gas and dust.