Your guide to the Solar System and the night sky
🌎 Location: Greenwich, United Kingdom [change]

Messier 21 - Open Cluster

Messier 21 is a Open Cluster in the Sagittarius constellation. Messier 21 is situated close to the celestial equator and, as such, it is at least partly visible from both hemispheres in certain times of the year.

Messier 21
Open Cluster
Sagittarius
Available Resources for Messier 21 - Open Cluster

Photometric information of Messier 21

The following table lists the magnitude of Messier 21 in different bands of the electomagnetic spectrum (when available), from the B band (445nm wavelength, corresponding to the Blue color), to the V band ( 551nm wavelength, corresponding to Green/Yellow color), to the J, H, K bands (corresponding to 1220nm, 1630nm, 2190nm wavelengths respectively, which are colors not visible to the human eye).

5.9

For more information about photometry in astronomy, check the photometric system article on Wikipedia.

Apparent size of Messier 21

The following table reports Messier 21 apparent angular size. The green area displayed on top of the DSS2 image of Messier 21 is a visual representation of it.
6 arcmin
6 arcmin

Digitized Sky Survey image of Messier 21

The image below is a photograph of Messier 21 from the Digitized Sky Survey 2 (DSS2 - see the credits section) taken in the red channel. The area of sky represented in the image is 0.5x0.5 degrees (30x30 arcmins).

Image of Messier 21 - Open Cluster star
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DSS2 image of Messier 21 in the Red band. The green region on the image is a representation of the major (6 arcmin) and minor (6 arcmin) axes of the object's apparent size.

Celestial coordinates and finder chart of Messier 21

Celestial coordinates for the J2000 equinox of Messier 21 are provided in the following table:

18h 04m 13s
-22° 29’ 23”

The simplified sky charts below show the position of Messier 21 in the sky. The first chart has a field of view of 60° while the second one has a field of view of 10°.

Finder chart Messier 21 - Open Cluster star
Simplified finder chart for Messier 21 - Open Cluster.

Finder chart Messier 21 - Open Cluster star
Simplified finder chart for Messier 21 - Open Cluster.

Rise ans set times of Messier 21 from your location

Location: Greenwich, United Kingdom [change]
Latitude: 51° 28’ 47” N
Longitude: 0° 00’ 00” E
Timezone: Europe/London

Today's Messier 21 - Open Cluster rise, transit and set times from Greenwich, United Kingdom [change] are the following (all times relative to the local timezone Europe/London):

Azimuth: 112.5°
Max altitude: 16.0°
Azimuth: 247.5°
Messier 21 - Open Cluster is below the horizon from Greenwich, United Kingdom