About IC 1821
IC 1821 is an uncommon galaxy. It sits in the constellation Ari.
Not one galaxy but two, locked in a gravitational embrace. Encounters like this shred spiral arms and trigger furious bursts of star formation.
Uncommon galaxy 31 EP
IC 1821
RA 39.1089° · Dec 13.7796° · openngc
Score breakdown
· 3 badgesUncommon 34 pts → Rare
- Galaxy +14
- Interacting galaxy pair +14
- On the zodiac +3
Total score 31
3 more points to reach Rare.
Badges
- Galaxy · +14
- Interacting galaxy pair · +14
- On the zodiac · +3
Trivia
What it actually is
- What it actually is. Not one galaxy but two, locked in a gravitational embrace. Encounters like this shred spiral arms and trigger furious bursts of star formation.
Sense of scale
- Sense of scale. Galaxies pass through each other almost without collisions — the stars are so far apart that they simply miss.
- 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 Aries.
- 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 October — that's when to go looking.
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
- Ari
- dso type
- GPair
- name
- IC 1821
- size arcmin
- 1
How to see it
Look for IC 1821 in the constellation Ari.
Like any astronomical target, IC 1821 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 1821 is an uncommon galaxy
IC 1821 scores 31 points on Spacedle's rarity scale, which places it in the uncommon tier. Another 3 points would lift it into a rarer tier.
That score comes from 3 science badges — Galaxy, Interacting galaxy pair 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.