Wide Field STELLA Imaging Photometer
WiFSIP
Band
State
Description
The WHT is part of the Isaac Newton Group of Telescopes (ING) that also operates the Isaac Newton Telescope and the Jacobus Kapteyn Telescope. The ING is owned and operated jointly by the Particle Physics and Astronomy Research Council (PPARC) of the United Kingdom, the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO) of the Netherlands and the Instituto de Astrofísica de Canarias (IAC) of Spain.
History
The advent of the WHT led SERC to negotiate a 20% participation by the Netherlands in 1981. That year was also the 200th anniversary of Herschel's discovery of Uranus, and the name of the new telescope was announced. Construction of the telescope building began in 1983 and first light on the telescope took place on 1 June 1987.
Results
For some time, astronomers considered using type Ia supernovae to determine the extragalactic distance scale. Supernovae of this type occur in the late stages of evolution of a binary system consisting of a white dwarf star orbiting a companion star. When the white dwarf mass reaches a critical value, the nuclear fuel ignites explosively, leading to an immense brightening of the star. The intrinsic luminosity of the explosion is thought to be independent of distance and therefore usable as a 'standard candle'. The distances and redshifts of these supernovae provide a measure of the deceleration parameter of the Universe and hence can be used to determine the ratio of the present density of the Universe to the critical density. Observations at the WHT of type Ia supernovae led in the 1990s to the discovery of the most distant supernovae ever observed, allowing astronomers to conclude that we live in an accelerating Universe, i.e. one that will expand with increasing velocity.
