Nebula
Sh2-184
H II region
A cloud of ionised hydrogen (H II region): a stellar nursery glowing in the ultraviolet light of the young, hot O and B stars inside it. The distance is measured from the parallax of masers in the region.
| Type | Nebula |
|---|---|
| Constellation | Cassiopeia |
| Distance | 2,820 pc (9.2 thousand ly) |
| Diameter | 97.2 ly |
| WISE name | G123.155-06.306 |
| Catalogue status | Known H II region |
| Source | WISE H II Catalog v3.0 |
| Right ascension (J2000) | 0h 53m 02.9s |
| Declination (J2000) | +56° 33′ 55″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 33° S. North of latitude 33° N it never sets. It stands highest at midnight in October, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 9,198 years ago. At that time the first farming villages were being founded; there was no writing yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 163 million years.