ALPACA will be a wide-field telescope employing an 8-meter rotating liquid mirror. Equipped with a large mosaic CCD camera, it will scan a long strip of sky two and a half degrees wide. As the Earth rotates, all objects in this strip will pass through the field of view of the telescope and be measured.

Optical Design

The optical design is a modified Baker-Paul 3-mirror reflecting system. Light from the 8-meter primary mirror is collimated by the convex secondary mirror, and then refocussed by a concave tertiary mirror. This design gives exceptionally-good images over a very wide field. For the ALPACA design, the images are less than 0.25 arcseconds (RMS spot diameter) over the entire 2.5-degree field of view. Atmospheric seeing will therefore be the primary factor determining the delivered image quality.



Last updated: 2004/04/08