About NGC 6791
NGC 6791 is a common cluster. It sits in the constellation Lyr and shines at apparent magnitude 9.5.
An open cluster: a few hundred stars born together out of one collapsing cloud, still drifting along in loose formation.
Common cluster 20 EP
NGC 6791
RA 290.2217° · Dec 37.7719° · openngc
Score breakdown
· 3 badgesCommon 22 pts → Uncommon
- Coming towards us +10
- Star cluster +7
- Open cluster +3
Total score 20
2 more points to reach Uncommon.
Badges
- Star cluster · +7
- Open cluster · +3
- 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
- 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
- How to spot it. At magnitude 9.5 you'll want a small backyard telescope, over in Lyra.
- 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 July — that's when to go looking.
Its true colour
- Its true colour. Open clusters look blue-white because they are young — their hottest, bluest stars have not had time to die yet.
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
- Lyr
- dso type
- OCl
- mag
- 9.5
- name
- NGC 6791
- radial velocity kms
- -47
- size arcmin
- 6.3
Nearby objects
- Rare Kepler-156 b exoplanet · <0.1° away
- Uncommon Kepler-156 c exoplanet · <0.1° away
- Uncommon Kepler-1777 b exoplanet · <0.1° away
- Uncommon Kepler-19 c exoplanet · 0.2° away
- Uncommon Kepler-19 d exoplanet · 0.2° away
- Rare Kepler-19 b exoplanet · 0.2° away
- Rare HIP 95024 star · 0.2° away
- Uncommon Kepler-1172 b exoplanet · 0.2° away
How to see it
Look for NGC 6791 in the constellation Lyr. At apparent magnitude 9.5, a small backyard telescope will bring it into view.
Like any astronomical target, NGC 6791 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 6791 is a common cluster
NGC 6791 scores 20 points on Spacedle's rarity scale, which places it in the common tier. Another 2 points would lift it into a rarer tier.
That score comes from 3 science badges — Star cluster, Open cluster 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.