SuperWASP is an extremely wide field robotic camera. It is sited at the Roque de los Muchachos Observatory. As its name suggests SuperWASP is designed to detect extrasolar planets via the transit technique around relatively bright stars. SuperWASP is used as a survey instrument - capable of imaging the entire visible sky every 45 minutes or so. The instrument is managed by a Consortium of UK and Spanish based astronomers (the WASP Consortium). The data rate from the instrument is so large that the Consortium have developed a dedicated reduction pipeline and archive for the extracted light curves. After a short propriety period the data is available to the general astronomical community.
SuperWASP was inaugurated in April 2004. Due to snow on the mountain during this period, in the interests of safety, the facility was remotely controlled by the Mayor of Garafia using a laptop at the Isaac Newton Group's Sea Level Office.
SuperWASP is composed of up to eight individual cameras each having a 200mm f1.8 lens imaging onto a thermoelectrically cooled 2048x2048 pixel thinned CCD detector. This gives it an angular scale of about 14 arc seconds per pixel. At this scale even at dark moon the night sky is sufficiently bright that our magnitude limit for the exoplanet work is about 13th magnitude (which matches the high resolution spectroscopic capabilities of 10m sized telescopes).
The development of SuperWASP can be traced back to the successful series of COmet CAMeras, at the Isaac Newton Group of Telescopes during the 1990's. Built with cheap components but using observatory grade large format CCD detectors, COCAM was used to take the discovery images of the Sodium Tail of Comet Hale Bopp. In 2000 a more commercial version of the camera was run for a 3 month period collecting data specifically to demonstrate the photometric capabilities of this type of instrument. WASP0 was a success and produced at least 3 scientific papers showing that even this equipment was capable of millimag accuracy photometry. More importantly WASP0 was a catalyst in attracting funding to produce a far more scientifically capable instrument.
The SuperWASP enclosure contains two rooms. The first contains the camera itself while the second all the associated computing. The roof above the camera is controllable via a 3m long hydraulic ram.
SuperWASP is built around a high quality robotic mount which is capable of slewing at anything up to 30 degrees per second. In the interests of longevity we run it at a more leisurely 10 degrees per second. Within the mount a custom cradle supports sophisticated CCD cameras. The air conditioned computer room contains sufficient computing needed to control and monitor the observatory (including GPS time service and weather station) along with data acquisition and archiving. The data rate from the instrument can be up to 100GB per night all of which has to be archived before the start of the next nights observing. All functions of the observatory can be controlled remotely.
In the second season of SuperWASP observing the instrument will not only continue with the exoplanet project but will also start nightly all sky monitoring. With these optics sky brightness limits the detection of faint objects to about 16th magnitude. However, after the exoplanet project we will exchange the optics for longer focal length lenses enabling nightly all sky photometry with good spatial sampling down to about 18th magnitude, thus enabling a wealth of new projects to be attempted.
We are also embarking on a real time reduction system. While ambiguous this could lead to early identification of transient phenomena (eg supernovae) and followup using other robotic facilities.
Its still early days for SuperWASP, even with only a fraction of the first years data reduced with a level of accuracy sufficient to detect exoplanet transits we still have a number of genuine candidates. These objects are sufficiently bright that catalogue data is available (eg USNO, 2MASS etc) which has been vital as a first stage in eliminating unlikely host stars. The next stage in our followup involves spectroscopy at the WHT and subsequently detailed multicolour transit photometry and orbital spectroscopy.
What is already clear is that SuperWASP will discover huge numbers of variable stars (mostly pulsators and eclipsing binaries) and shear quantity of these promises to add significantly to those currently known.