About NGC 6991
NGC 6991 is an uncommon cluster. It lies about 1,847.9 light-years from Earth and sits in the constellation Cyg.
An open cluster: a few hundred stars born together out of one collapsing cloud, still drifting along in loose formation.
Uncommon cluster 31 EP
NGC 6991
RA 313.7167° · Dec 47.4617° · openngc
Score breakdown
· 5 badgesUncommon 34 pts → Rare
- Coming towards us +10
- Star cluster +7
- Distant (over 1,000 light-years) +6
- Big on the sky +5
- Open cluster +3
Total score 31
3 more points to reach Rare.
Badges
- Star cluster · +7
- Distant (over 1,000 light-years) · +6
- Open cluster · +3
- Big on the sky · +5
- Coming towards us · +10
Trivia
What it actually is
- What it actually is. An open cluster: a few hundred stars born together out of one collapsing cloud, still drifting along in loose formation.
Sense of scale
- In perspective. Far away by human standards, yet still a local address inside the Milky Way's spiral arms.
- Sense of scale. Gravity is not strong enough to hold it. Within a few hundred million years these siblings will be scattered right around the galaxy.
Find it in the sky
- Where to look. You'll find it in the constellation Cygnus.
- Northern sky. It rides the northern half of the sky — an easier target the further north you are.
- Best time of year. It stands highest in the middle of the night around August — that's when to go looking.
Could we get there?
- Verdict. Impossible with our current technology — and the next millennium of it.
Getting there
- Aboard Voyager 1. ≈ 32.5 million years at Voyager 1's speed (17 km/s).
Properties
- constellation
- Cyg
- dist ly
- 1847.9093
- dso type
- OCl
- name
- NGC 6991
- radial velocity kms
- -12
- size arcmin
- 23
Nearby objects
How to see it
Look for NGC 6991 in the constellation Cyg.
Like any astronomical target, NGC 6991 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 6991 is an uncommon cluster
NGC 6991 scores 31 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 3 points would lift it into a rarer tier.
That score comes from 5 science badges — Star cluster, Distant (over 1,000 light-years), Open cluster, Big on the sky 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.