Pulsar
PSR B1745-20A (J1748-2021A)
Radio pulsar · in the globular cluster NGC6440
A neutron star spinning once every 0.289 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 | 288.6 ms |
| Period derivative | 4.0×10⁻¹⁶ s/s |
| Characteristic age | 12 million years |
| Magnetic field | 3.4×10¹¹ G |
| Spin-down luminosity | 6.6×10³² erg/s |
| Dispersion measure | 219.4 pc/cm³ |
| Distance | 8,200 pc (26.7 thousand ly) |
| Location | in the globular cluster NGC6440 |
| Discovery | 1989 · misc, htru_pks, pksmb |
| Source | ATNF Pulsar Catalogue |
| Right ascension (J2000) | 17h 48m 52.7s |
| Declination (J2000) | −20° 21′ 40″ |
In the sky
Visible from the whole Southern Hemisphere and north to latitude 70° N. South of latitude 70° 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 27 thousand years ago. At that time Homo sapiens was spreading out of Africa; there was no farming yet. At the speed of Voyager 1, the fastest craft leaving the Solar System (16.9 km per second), the trip would take 474 million years.