About Owl Cluster
Owl Cluster is a rare cluster. It sits in the constellation Cas and shines at apparent magnitude 6.4.
An open cluster: a few hundred stars born together out of one collapsing cloud, still drifting along in loose formation.
Rare cluster 38 EP
Owl Cluster
RA 19.8860° · Dec 58.2907° · openngc
Score breakdown
· 6 badgesRare 50 pts → Epic
- Coming towards us +10
- Has a proper name +8
- Star cluster +7
- Bright deep-sky object +6
- Never sets (northern circumpolar) +4
- Open cluster +3
Total score 38
12 more points to reach Epic.
Badges
- Star cluster · +7
- Bright deep-sky object · +6
- Has a proper name · +8
- Open cluster · +3
- Never sets (northern circumpolar) · +4
- 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 6.4 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cassiopeia.
- 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 October — 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.
What's in a name
- Named. Notable enough to have earned a proper name, not just a catalogue number.
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
- Cas
- dso type
- OCl
- mag
- 6.4
- name
- Owl Cluster
- named
- yes
- radial velocity kms
- -12
- size arcmin
- 7.8
Nearby objects
How to see it
Look for Owl Cluster in the constellation Cas. At apparent magnitude 6.4, it is an easy target for binoculars.
Like any astronomical target, Owl Cluster 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 Owl Cluster is a rare cluster
Owl Cluster scores 38 points on Spacedle's rarity scale, which places it in the rare tier. Another 12 points would lift it into a rarer tier.
That score comes from 6 science badges — Star cluster, Bright deep-sky object, Has a proper name, Open cluster, Never sets (northern circumpolar) 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.