- Beta Ophiuchi or β Ophiuchi, also named Cebalrai /ˌsɛbəlˈreɪ.iː/, is a star in the equatorial constellation of Ophiuchus. The apparent visual magnitude of this star is 2.7, which is readily visible to the naked eye even from urban skies. The distance to this star can be estimated using parallax measurements, yielding a value of 83.4 light-years (25.6 parsecs) from the Sun.
- Utility frequency (Wikipedia)
The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user. In large parts of the world this is 50 Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains electricity by country.