About NGC 6603
NGC 6603 is a common cluster. It sits in the constellation Sgr and shines at apparent magnitude 11.1.
An open cluster: a few hundred stars born together out of one collapsing cloud, still drifting along in loose formation.
Common cluster 21 EP
NGC 6603
RA 274.6124° · Dec -18.4061° · openngc
Score breakdown
· 4 badgesCommon 22 pts → Uncommon
- Toward the galactic centre +8
- Star cluster +7
- Open cluster +3
- On the zodiac +3
Total score 21
1 more point to reach Uncommon.
Badges
- Star cluster · +7
- Open cluster · +3
- Toward the galactic centre · +8
- On the zodiac · +3
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 11.1 you'll want a small backyard telescope, over in 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. 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
- Sgr
- dso type
- OCl
- mag
- 11.1
- name
- NGC 6603
- radial velocity kms
- 18
- redshift
- 0.0001
- size arcmin
- 4.2
How to see it
Look for NGC 6603 in the constellation Sgr. At apparent magnitude 11.1, a small backyard telescope will bring it into view.
Like any astronomical target, NGC 6603 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 6603 is a common cluster
NGC 6603 scores 21 points on Spacedle's rarity scale, which places it in the common tier. Another 1 point would lift it into a rarer tier.
That score comes from 4 science badges — Star cluster, Open cluster, Toward the galactic centre and On the zodiac — 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.