The Telescopes of the Isaac Newton Group

THERE ARE THREE telescopes in the Isaac Newton Group :

• 4.2 m William Herschel Telescope (WHT)
• 2.5 m Isaac Newton Telescope (INT)
• 1.0 m Jacobus Kapteyn Telescope (JKT)

The three telescopes have complementary roles:
 
 

- The WHT, with its 4.2 m diameter primary mirror , is the largest telescope in Western Europe. It was first operational in August 1987. It is a general purpose telescope equipped with instruments for a wide range of astronomical observations. WHT overall height from base is 18.1 m. Logo: [gif,35k][jpg,29k] . This is a scheme of the light path inside the telescope.
- The INT was originally used at Herstmonceux in the UK, but was moved to La Palma and has been rebuilt with a new mirror and new instrumentation. It has a 2.5 m diameter primary mirror and is mostly used for wide-field imaging and spectroscopy. It became operational in May 1984. Logo: [gif,34k][jpg,103k].
- The JKT has a primary mirror of 1 m diameter. It is mainly used for observing relatively bright objects. It was first operational in May 1984. Logo: [gif,33k][jpg,27k].

Considering the weight of the instruments, the telescopes move with astounding precision. The WHT, for example, weighs 190 tonnes and has a pointing accuracy of 1 - 1.5 arcseconds, which compares to the diameter of a coin seen at a distance of 2 km. It can track the stars with an accuracy even ten times better!