Ptolemy Cluster (M7)
Also known as M7 · M 7 · Ptolemy Cluster · NGC 6475 · Ptolemy's Cluster
Ptolemy Cluster (M7) is an open star cluster in the constellation Scorpius, about 930 light-years from Earth.
Facts
| Type | Open star cluster |
|---|---|
| Constellation | Scorpius |
| Position (J2000) | 17h 53m 51s, −34° 47′ |
| Distance | 930 light-years (its light set off about 930 years ago) |
| Brightness | magnitude 3.3 (smaller is brighter; the faintest stars the eye sees are about 6) |
| Size on the sky | 100.1′ × 100.1′ (the full Moon is about 31′) |
| Filter | No filter (It shines in starlight of every colour, so a nebula filter would only dim it; a dark sky helps more.) |
| Studied in | 424 scientific papers (SIMBAD) |
When and how to see it
Ptolemy Cluster (M7) is highest in the sky at midnight in June. From India (about 20° N) it climbs to about 35° above the horizon; from 50° N, to about 5°. To see it you need the naked eye, even from a town.
Heights are worked out for India and for 50° N. Set your location in Settings to see them for where you are.
For tonight's best time from your own town, the darkness and the Moon, open it on the map and see its "Tonight from your location" card.
More in Scorpius
- Butterfly Cluster (M6)
- Butterfly Nebula
- Cat's Paw Nebula
- Fried Egg Nebula
- M4 (NGC 6121)
- M80 (NGC 6093)
- Prawn Nebula
- War and Peace Nebula
Everything in Scorpius · All 88 constellations · All sky objects
Data: SIMBAD (CDS, Strasbourg; the site's weekly copy) · OpenNGC · Data sources & credits