About IC 921
IC 921 is an uncommon galaxy. It sits in the constellation UMa.
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.
Uncommon galaxy 22 EP
IC 921
RA 205.7833° · Dec 55.6512° · openngc
Score breakdown
· 3 badgesUncommon 34 pts → Rare
- Galaxy +14
- Elliptical galaxy +4
- Never sets (northern circumpolar) +4
Total score 22
12 more points to reach Rare.
Badges
- Galaxy · +14
- Elliptical galaxy · +4
- Never sets (northern circumpolar) · +4
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.
- Elliptical. An elliptical galaxy: a smooth swarm of stars on randomly tilted orbits, with almost no cold gas left to build anything new.
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
- Where to look. You'll find it in the constellation Ursa Major.
- 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
- Red and dead. Ellipticals glow reddish because every short-lived blue star they ever had has already died. Astronomers call them 'red and dead'.
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
- UMa
- dso type
- G
- hubble
- E
- name
- IC 921
- size arcmin
- 0.29
- surface brightness
- 23.46
How to see it
Look for IC 921 in the constellation UMa.
Like any astronomical target, IC 921 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 921 is an uncommon galaxy
IC 921 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, Elliptical galaxy and Never sets (northern circumpolar) — 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.