Tukuk-OS🔭 M13 — Great Hercules Cluster
Globular cluster in Hercules
M13, Great Hercules Cluster is a globular cluster in the constellation Hercules, with an apparent magnitude of about 5.8, roughly 22.2 thousand light-years away.
Data
| Catalogue designation | M13 |
|---|---|
| Common name | Great Hercules Cluster |
| Object type | Globular cluster |
| Constellation | Hercules |
| NGC / IC | NGC 6205 |
| Apparent magnitude | 5.8 |
| Distance (approx.) | 22.2 thousand light-years |
What a globular cluster is
A dense, spheroidal ball of hundreds of thousands of old stars orbiting a galaxy’s halo. Through a small telescope they look like fuzzy stars; in a large one they resolve into glittering swarms.
How far is M13, really?
The catalogue puts M13 at roughly 22.2 thousand light-years away — about 6,807 parsecs. A light-year is the distance light covers in one year, some 9.46 trillion kilometres, so this is how long the light now entering your eyes has been travelling. For scale: slightly more than the time since the last ice age reached its peak. A message sent there today would need to wait twice that many years for a reply, which is why astronomers always look backwards: every telescope is a time machine with the dial set by distance.
What will show it to you?
M13 carries an apparent magnitude of about 5.8. bright enough for the naked eye from a genuinely dark site — look for it on a moonless night far from town lights. The magnitude scale runs backwards — smaller is brighter, and each whole step is a factor of about 2.5 in light — so 6 is the traditional naked-eye ceiling on a good night, and every number below it is progressively easier.
Finding its home constellation
M13 lies inside the official borders of Hercules, whose name means “Hercules (mythological character)”, a region of 1,225 square degrees. Practical way to find it: learn Hercules’s pattern first — its brightest star, Kornephoros, is the anchor point, then star-hop from there. The constellation’s own page lists every other Messier object that shares its borders, which usually means a night’s hunting is hiding in one patch of sky.
Other Messier objects in Hercules: M92.
More globular clusters in the catalogue: M2 · M3 · M4 · M5 · M9 · M10 · M12 · M14 · M15 · M19 … and 18 more on the Messier hub. The full catalogue groups all 110 the same way.