About Harvard 20
Harvard 20 is a common cluster. It sits in the constellation Sge and shines at apparent magnitude 7.7.
An open cluster: a few hundred stars born together out of one collapsing cloud, still drifting along in loose formation.
Common cluster 16 EP
Harvard 20
RA 298.2750° · Dec 18.3333° · openngc
Score breakdown
· 3 badgesCommon 22 pts → Uncommon
- Star cluster +7
- Bright deep-sky object +6
- Open cluster +3
Total score 16
6 more points to reach Uncommon.
Badges
- Star cluster · +7
- Bright deep-sky object · +6
- Open cluster · +3
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 7.7 it is just past naked-eye reach — ordinary binoculars will pull it in, over in Sagitta.
- 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 July — 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.
Properties
- constellation
- Sge
- dso type
- OCl
- mag
- 7.7
- name
- Harvard 20
- radial velocity kms
- 6
- redshift
- 0
- size arcmin
- 5.1
Nearby objects
How to see it
Look for Harvard 20 in the constellation Sge. At apparent magnitude 7.7, it is an easy target for binoculars.
Like any astronomical target, Harvard 20 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 Harvard 20 is a common cluster
Harvard 20 scores 16 points on Spacedle's rarity scale, which places it in the common tier. Another 6 points would lift it into a rarer tier.
That score comes from 3 science badges — Star cluster, Bright deep-sky object and Open cluster — 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.