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Rare galaxy 38 EP

IC 4584

RA 240.0511° · Dec -66.3833° · openngc

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Score breakdown

· 5 badges
38 pts · Rare
Rare 50 pts → Epic
  • Galaxy +14
  • Ghostly low surface brightness +10
  • Outside our galaxy entirely +6
  • Spiral galaxy +5
  • Faint fuzzy (mag > 13) +3
Total score 38

12 more points to reach Epic.

Badges

  • Galaxy · +14
  • Outside our galaxy entirely · +6
  • Spiral galaxy · +5
  • Ghostly low surface brightness · +10
  • Faint fuzzy (mag > 13) · +3

Trivia

What it actually is

  • What it actually is. A galaxy: a gravitationally bound city of stars, gas and dark matter, turning so slowly that a single rotation takes hundreds of millions of years.
  • Spiral. A spiral galaxy. Those arms are not solid structures but traffic jams — density waves that stars drift into and out of as they orbit.

Sense of scale

  • In perspective. Deep in the extragalactic distance — further than the entire Virgo Cluster of galaxies.
  • Scale. Home to hundreds of billions of stars — a universe unto itself, and every one of those points of light could have planets.

Find it in the sky

  • How to spot it. At magnitude 15.8 it is far too faint for the eye: this one belongs to cameras and long exposures, over in Triangulum Australe.
  • Southern sky only. So far south it never rises for most of the northern hemisphere. To see it you'd have to travel to Chile, South Africa or Australia.
  • Best time of year. It stands highest in the middle of the night around May — that's when to go looking.

Could we get there?

  • Verdict. Impossible with our current technology — and the next millennium of it.

Properties

constellation
TrA
dist ly
171923610.3898
dso type
G
hubble
Sc
mag
15.78
name
IC 4584
radial velocity kms
3667
redshift
0.0123
size arcmin
1.96
surface brightness
25.83

About IC 4584

IC 4584 is a rare galaxy. It lies about 171,923,610.4 light-years from Earth, sits in the constellation TrA and shines at apparent magnitude 15.78.

A galaxy: a gravitationally bound city of stars, gas and dark matter, turning so slowly that a single rotation takes hundreds of millions of years.

How to see it

Look for IC 4584 in the constellation TrA. At apparent magnitude 15.78, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, IC 4584 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 4584 is a rare galaxy

IC 4584 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 5 science badges — Galaxy, Outside our galaxy entirely, Spiral galaxy, Ghostly low surface brightness and Faint fuzzy (mag > 13) — 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.