About NGC 654
NGC 654 is an uncommon cluster. It sits in the constellation Cas and shines at apparent magnitude 6.5.
An open cluster: a few hundred stars born together out of one collapsing cloud, still drifting along in loose formation.
Uncommon cluster 30 EP
NGC 654
RA 25.9976° · Dec 61.8827° · openngc
Score breakdown
· 5 badgesUncommon 34 pts → Rare
- Coming towards us +10
- Star cluster +7
- Bright deep-sky object +6
- Never sets (northern circumpolar) +4
- Open cluster +3
Total score 30
4 more points to reach Rare.
Badges
- Star cluster · +7
- Bright deep-sky object · +6
- 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 6.5 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Cassiopeia.
- Never sets. So far north that from Britain, Canada or northern Europe it never dips below the horizon — it is up every clear night of the year.
- 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.
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
- 6.5
- name
- NGC 654
- radial velocity kms
- -39
- size arcmin
- 6.3
Nearby objects
How to see it
Look for NGC 654 in the constellation Cas. At apparent magnitude 6.5, it is an easy target for binoculars.
Like any astronomical target, NGC 654 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 654 is an uncommon cluster
NGC 654 scores 30 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 4 points would lift it into a rarer tier.
That score comes from 5 science badges — Star cluster, Bright deep-sky object, 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.