Messier 21, also known as M21, NGC 6531 or Webb's Cross, is a young, tightly packed open cluster of stars in the constellation Sagittarius, discovered and catalogued by Charles Messier on 5 June 1764. It contains a few blue giant stars amid mostly small, dim stars, forms part of the Sagittarius OB1 association, and lies near the Trifid Nebula without being physically associated with it.
Facts
Classification
Constellation Discovery Year In the Other Atlases
In Constellation
Also in Divinity Atlas: the constellation this subject lies in.
Sources
1. Wikidata: Messier 21
- Wikidata Q11383, class allow-list match (w-wdresolver-0926)
- wikidata-q11383 Wikidata claim (w-bbfill-edspace5-0927)
View the Source2. Wikipedia (space and spaceflight articles)
Wikimedia Foundation
Messier 21 (Wikipedia)
Messier 21, Wikipedia - lead section, catalogue classification
Messier 21 or M21, also designated NGC 6531 or Webb's Cross, is an open cluster of stars located to the north-east of Sagittarius in the night sky, close to the Messier objects M20 to M25 (except M24).
In Group: Open Clusters, Lead sentence
Messier 21 or M21, also designated NGC 6531 or Webb's Cross, is an open cluster of stars located to the north-east of Sagittarius in the night sky, close to the Messier objects M20 to M25 (except M24).
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