Assertion: nebula's structure | /r/Synonym | the hourglass nebula
Facets:
Source sentences:
text: The Lagoon Nebula also contains at its centre a structure known as the Hourglass Nebula (so named by John Herschel), which should not be confused with the better known Engraved Hourglass Nebula in the constellation of Musca.
text: The Lagoon Nebula contains at its center a structure known as the Hourglass Nebula (so named by John Herschel), which should not be confused with the better known Hourglass Nebula (see above).