APOD: 2025 September 17 Б Nebulas and Clusters in Sagittarius
Explanation:
Can you spot famous celestial objects in this image?
18th-century astronomer
Charles
Messier cataloged only two of them: the bright
Lagoon Nebula (M8) at the bottom, and the colorful
Trifid Nebula (M20) at the upper right.
The one on the left that resembles a
cat's paw is
NGC 6559,
and it is much fainter than the other two.
Even harder to spot are the thin blue filaments on the left, from
supernova remnant (SNR G007.5-01.7).
Their glow comes from small amounts of
glowing oxygen atoms that are so faint that it took over
17 hours of exposure
with just one blue color to bring up.
Framing this scene of stellar birth and death are two star clusters: the
open cluster
M21
just above Trifid, and the
globular cluster
NGC 6544 at lower left.
Authors & editors:
Robert Nemiroff
(MTU) &
Jerry Bonnell
(USRA)
NASA Web Site Statements, Warnings,
and Disclaimers
NASA Official: Jay Norris.
Specific
rights apply.
A service of:
LHEA at
NASA /
GSFC
& Michigan Tech. U.
