Nomenclature of Interstellar Objects and Stars
Names are common enough for solar system bodies, but generally stars don't have names, they have identifiers from various catalogues.
In the case of Pulsars. they are named by their location in the sky.  Just like Earth has longitude and latitude, every point in the sky has a &quot;right ascension&quot; and &quot;declination&quot;.  Due to the slow movement of the Earth's axis, to identify the location in the sky you also need to mention a date, though you can look up the positions of stars in 1950 (B1950) or 2000 (J2000). Also, for historic reasons, the angle of right ascension (or &quot;longitude&quot;) is measured in hours and minutes (24hr = 360 degrees)
Now the Black Widow pulsar is located at 19hr 57 minutes of right ascension and +20 degrees of declination (in the B1950 coordinates).  So its designation is PSR B1957+20.