Pulsar
PSR B1809-173 (J1812-1718)
Radio pulsar
A neutron star spinning once every 1.21 seconds; the beams from its magnetic poles sweep across Earth on every turn. Period, spin-down, distance and orbit come from the ATNF Pulsar Catalogue; the beam geometry is illustrative.
| Type | Pulsar |
|---|---|
| Constellation | Sagittarius |
| Period | 1.205 s |
| Period derivative | 1.9×10⁻¹⁴ s/s |
| Characteristic age | 1.0 million years |
| Magnetic field | 4.9×10¹² G |
| Spin-down luminosity | 4.3×10³² erg/s |
| Dispersion measure | 251.4 pc/cm³ |
| Distance | 3,659 pc (11.9 thousand ly) |
| Discovery | 1986 · jb2, htru_pks, pksmb |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 18h 12m 07.2s |
| Declination (J2000) | −17° 18′ 30″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 73° N. South of latitude 73° S it never sets. It stands highest at midnight in June, the best time to observe it.
Through a telescope from Earth
Light's journey
The light you see tonight set out 12 thousand 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 212 million years.