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Rare cluster 40 EP

IC 2581

RA 156.8715° · Dec -57.6173° · openngc

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Score breakdown

· 5 badges
40 pts · Rare
Rare 50 pts → Epic
  • Bright enough for the unaided eye +14
  • Coming towards us +10
  • Star cluster +7
  • Bright deep-sky object +6
  • Open cluster +3
Total score 40

10 more points to reach Epic.

Badges

  • Star cluster · +7
  • Bright deep-sky object · +6
  • Open cluster · +3
  • Coming towards us · +10
  • Bright enough for the unaided eye · +14

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 4.3 you can see it with your own eyes from a dark site, over in Carina.
  • 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 February — 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 Index Catalogue. The IC was the 1895 and 1908 supplement to the NGC — the first catalogue in history to be filled largely with objects found on photographic plates rather than by eye.

Properties

constellation
Car
dso type
OCl
mag
4.3
name
IC 2581
radial velocity kms
-5
size arcmin
6

Nearby objects

About IC 2581

IC 2581 is a rare cluster. It sits in the constellation Car and shines at apparent magnitude 4.3.

An open cluster: a few hundred stars born together out of one collapsing cloud, still drifting along in loose formation.

How to see it

Look for IC 2581 in the constellation Car. At apparent magnitude 4.3, it can be glimpsed with the unaided eye under dark skies.

Like any astronomical target, IC 2581 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 IC 2581 is a rare cluster

IC 2581 scores 40 points on Spacedle's rarity scale, which places it in the rare tier. Another 10 points would lift it into a rarer tier.

That score comes from 5 science badges — Star cluster, Bright deep-sky object, Open cluster, Coming towards us and Bright enough for the unaided eye — 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.