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Uncommon galaxy 22 EP

IC 3691

RA 190.7064° · Dec 22.7722° · openngc

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Score breakdown

· 3 badges
22 pts · Uncommon
Uncommon 34 pts → Rare
  • Galaxy +14
  • Spiral galaxy +5
  • Faint fuzzy (mag > 13) +3
Total score 22

12 more points to reach Rare.

Badges

  • Galaxy · +14
  • Spiral galaxy · +5
  • 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

  • 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 16.5 it is far too faint for the eye: this one belongs to cameras and long exposures, over in Coma Berenices.
  • 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 April — that's when to go looking.

Its true colour

  • Its true colour. Its colour is a census: blue where gas is still collapsing into hot young stars, yellow-red in the old, settled core.

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
Com
dso type
G
hubble
Sc
mag
16.47
name
IC 3691
size arcmin
0.38
surface brightness
22.86

Nearby objects

About IC 3691

IC 3691 is an uncommon galaxy. It sits in the constellation Com and shines at apparent magnitude 16.47.

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 3691 in the constellation Com. At apparent magnitude 16.47, it takes a larger telescope or a long-exposure image to capture.

Like any astronomical target, IC 3691 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 3691 is an uncommon galaxy

IC 3691 scores 22 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 12 points would lift it into a rarer tier.

That score comes from 3 science badges — Galaxy, Spiral galaxy 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.