M4
Where is M4?
Below the horizon after dark tonight in Scorpius. Rises 12:59.
- Rises
- 12:59
- Highest
- 16:28
- Sets
- 19:57
- Best after dark
- —
Can I see M4 tonight?
From London tonight, M4 isn’t above the horizon while the sky is dark. It rises at 12:59 and sets at 19:57, in daylight or twilight.
At magnitude 5.6, with its light spread out, it needs binoculars and a dark sky.
This is position and timing only: clouds, haze and light pollution aren’t included.
What does M4 look like?
Eyes
Under dark skies, a faint fuzzy spot near Antares.
Binoculars
A round, faint glow beside Antares.
Telescope
Resolves into stars in a 100 mm telescope, with a distinctive bar of stars across its center.
About M4
M4 is one of the closest globular clusters to Earth, about 7,200 light-years away. It is unusually loose for a globular, so even modest telescopes show many individual stars.
It lies just over a degree from bright Antares, making it one of the easiest globulars to find.
M4 was the first globular cluster in which individual stars were seen, by Charles Messier in 1764.
In 2002, the Hubble Space Telescope studied its faint white dwarfs, the cooling remains of old stars, to estimate the cluster’s age at around 12 to 13 billion years.
M4 also hosts a pulsar with a planet, sometimes called the Methuselah planet, one of the oldest planets known.
Dust between us and M4 dims it slightly, so it looks fainter than its closeness would suggest.
M4 is best seen on summer evenings from mid-northern latitudes, low in the south, and high overhead in winter evenings from the Southern Hemisphere.
Nearby in the sky
Questions
Why is M4 easy to resolve?
Sources: SkyMate; star chart: Wikidata (CC0). Positions computed for your place and time with astronomy-engine. Data & Licences