Sky Tonight

Santa Clara, US
37.4°/-122°
GMT -9

⌕

☾

Sky-Tonight.com / Nebulae and Deep-Sky Objects / M21

M21 Position and Visibility Tonight

Where is M21 right now?

M21 is located in the constellation Sagittarius. It is currently below the horizon and is not visible from your location.
Twilight begins at 18:48 local time. At that moment, M21 will be 30° above the horizon toward the south.

M21 visibility on 2026-08-24

M21 Visible from sunset until early morning

M21 rise and set timetable

	Time	Elevation
M21 rise	14:16
Moonrise, 83.8% illuminated	15:29	12°
Sunset	17:47	28°
Civil sunset	18:16	29°
Twilight start	18:48	30°
M21 transit	19:02	30°
Astronomical observing session begins	19:22	30°
M21 set	23:47
Moonset	00:52	-12°
Astronomical observing session ends	02:58	-36°

Track M21 Position Throughout the Night

← 24 August 2026 →

Time
Altitude
Azimuth

Shift the map to change the time and observe M21 changing position in the night sky.

M21 - Open Cluster

M21 is an open cluster located in the constellation Sagittarius. It was discovered by Charles Messier in 1764. The cluster contains a mix of young, hot stars and older stars.

M21 spans about 15 light-years across and contains around 57 stars. The cluster is approximately 4,250 light-years away from Earth and has an apparent magnitude of 6.5, making it visible with binoculars or a small telescope.

M21 — Image Gallery

DSS Blue

Blue images highlight younger, hotter stars that emit strongly at blue wavelengths.

DSS Red

Red images reveal older, cooler stars and emission nebulae glowing strongly in hydrogen-alpha light.

DSS Near-Infrared

Near-infrared images penetrate dust that obscures visible light and reveal hidden structures.

DSS Composite Image

DSS color images combine blue, red and often near-infrared exposures into a composite view.

The images come from the Digitized Sky Survey 2 (DSS2), produced at the Space Telescope Science Institute (STScI) under contract with NASA, using data from UK Science and Technology Facilities Council (STFC), European Southern Observatory (ESO), National Geographic Society-Palomar Observatory Sky Survey (POSS II).

Special thanks to National Optical Astronomy Observatory (NOAO), Royal Observatory, Edinburgh, California Institute of Technology for their significant contributions.

Finder Chart for M21

Double-click to unlock the map.

Object name	M21
Field of view
Limiting magnitude
M21 coordinates	18.0704, -22.49006
Center coordinates	18.0704, -22.49006

M21 Passage Through Night

Double-click to unlock the map.

Current position of M21

Time	14:24
Latitude	37.3541
Longitude	-121.955
Elevation	1°
Azimuth	120°

Here you can see the current position of M21 on the map, as well as its positions for rise and set. This tool lets you track its movement throughout the night with accurate, up-to-date information.

Annual motion of M21

M21 will remain visible until September 7, when it moves too close to the Sun and temporarily disappears from the night sky.

Date	Mon, 24 August 2026
Twilight start	19:18
Twilight end	02:51
Twilight duration	8h 34m
Rise	14:12
Set	23:43
Elevation at transit	30°
Transit time	18:58
Equatorial coordinates	RA: 18h 04m 13s", Dec: -22° 29' 24s
Magnitude	6
Constellation	Sagittarius

The graph illustrates the annual visibility pattern of M21, including its daily appearances and transit times. The vertical axis shows the hours of the day and the horizontal axis spans the year. The reddish area marks when the object is above the horizon, while the white line marks its daily transit.
You can also view detailed visibility information in a table with exact rise, transit, and set times for each date.

Astrometric and Physical Parameters of M21

Coordinates and Visibility

Right Ascension	18.0704°
Declination	-22.49006°
Magnitude	5.90
Constellation	Sagittarius
Elevation	1.3°
Azimuth	119.9°

Data Credits

The deep-sky information on this page comes from the OpenNGC project developed by Matteo Verga. OpenNGC provides detailed catalog data for nebulae, galaxies, clusters and other deep-sky objects.

For details or contributions, visit the official repository: OpenNGC GitHub.

Observation Settings