M21 (Open cluster)
R/B-band color composite image from the Second Digitized Sky Survey (DSS2), measuring 10 arcminutes across.
From Cambridge , M21 is visible in the morning sky, becoming accessible around 02:54, when it reaches an altitude of 21° above your south-eastern horizon. It will then reach its highest point in the sky at 04:25, 25° above your southern horizon. It will be lost to dawn twilight around 04:28, 25° above your southern horizon.
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Name
M21
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Object type
Open cluster
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Position
| Right ascension: | 18h04m [3] |
| Declination: | -22°29' [3] |
| Constellation: | Sagittarius |
| Magnitude: | 5.90 (V) [5] |
| Distance: | 1.2 kpc 3.9 klyr [2] |
Derived quantities
| Absolute mag (V): | -4.50 |
Sources