A birthday present for the William Herschel Telescope
The William Herschel Telescope is 25 years old today – first light was the 1st June 1987. For many years the Herschel was the biggest optical and infrared telescope in Europe, until Gran Telescopio Canarias opened in 2009. It’s main mirror is 4.2 m or 165? across which was huge when it opened, although that’s medium-sized these days. The telescope has so many different instruments that it’s been compared…