Supernova
CTB 104A (SNR G93.7-0.2)
Supernova remnant
The shock wave of a supernova expanding at thousands of kilometres per second: it sweeps up and heats the interstellar gas and shines in radio waves. The distance is estimated from the radio surface-brightness–diameter (Σ–D) relation and may be off by a factor of two.
| Type | Supernova |
|---|---|
| Constellation | Cygnus |
| Distance | 2,340 pc (7.6 thousand ly) · estimated |
| Diameter | 177.4 ly |
| Type | Shell type |
| Radio flux (1 GHz) | 65 Jy |
| Source | Green's SNR Catalogue |
| Right ascension (J2000) | 21h 29m 20.0s |
| Declination (J2000) | +50° 49′ 59″ |
In the sky
Visible from the whole Northern Hemisphere and south to latitude 39° S. North of latitude 39° N it never sets. It stands highest at midnight in August, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 7,632 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 135 million years.