About NGC 6540
NGC 6540 is a rare cluster. It sits in the constellation Sgr.
A globular cluster: hundreds of thousands of stars packed into a ball a few dozen light-years across, orbiting far out in the galaxy's halo.
Rare cluster 42 EP
NGC 6540
RA 271.5331° · Dec -27.7628° · openngc
Score breakdown
· 5 badgesRare 50 pts → Epic
- Globular cluster +14
- Coming towards us +10
- Toward the galactic centre +8
- Star cluster +7
- On the zodiac +3
Total score 42
8 more points to reach Epic.
Badges
- Star cluster · +7
- Globular cluster · +14
- Toward the galactic centre · +8
- On the zodiac · +3
- Coming towards us · +10
Trivia
What it actually is
- What it actually is. A globular cluster: hundreds of thousands of stars packed into a ball a few dozen light-years across, orbiting far out in the galaxy's halo.
Sense of scale
- Sense of scale. Stand on a planet near its core and the night sky would blaze with thousands of stars brighter than Venus. There would be no true darkness.
Find it in the sky
- Where to look. You'll find it in the constellation Sagittarius.
- Southern sky. It rides the southern half of the sky — an easier target the further south you are.
- Best time of year. It stands highest in the middle of the night around June — that's when to go looking.
Its true colour
- Its true colour. Globulars glow yellow-orange because they are ancient — around 12 billion years old, with every hot blue star long since burned out.
How we came to know it
- The New General Catalogue. Its NGC number comes from J. L. E. Dreyer's 1888 catalogue, itself built on decades of sky sweeps by William Herschel and his sister Caroline.
Properties
- constellation
- Sgr
- dso type
- GCl
- name
- NGC 6540
- radial velocity kms
- -18
- size arcmin
- 4.08
Nearby objects
- Rare OGLE-2012-BLG-0563L b exoplanet · <0.1° away
- Uncommon MOA-2016-BLG-227L b exoplanet · <0.1° away
- Uncommon KMT-2024-BLG-1044L b exoplanet · 0.2° away
- Uncommon HD 165269 star · 0.3° away
- Uncommon KMT-2024-BLG-0404L c exoplanet · 0.4° away
- Uncommon KMT-2024-BLG-0404L b exoplanet · 0.4° away
- Uncommon J1804-28 pulsar · 0.5° away
- Uncommon MOA-2010-BLG-353L b exoplanet · 0.5° away
How to see it
Look for NGC 6540 in the constellation Sgr.
Like any astronomical target, NGC 6540 is best seen from a dark site away from city lights, and when it is above the horizon depends on your latitude and the time of year. The visibility panel above works out tonight's viewing window for your saved location.
Why NGC 6540 is a rare cluster
NGC 6540 scores 42 points on Spacedle's rarity scale, which places it in the rare tier. Another 8 points would lift it into a rarer tier.
That score comes from 5 science badges — Star cluster, Globular cluster, Toward the galactic centre, On the zodiac and Coming towards us — each earned for a real, measurable property of the object. Rarity on Spacedle is never random: the more remarkable an object's astrophysics, the more badges it collects, the higher it scores, and the rarer it ranks.