抚仙湖太阳观测和研究基地知识库

Two optical designs for wide field of view Cherenkov telescope array (WFCTA), a major component of the LHAASO project, are presented. The designs aim at obtaining a good quality imaging for a cosmic ray air shower over a field of view (FOV) of 16° × 14°. The Fresnel lens telescope, F/0.95, has a spherical reflective primary mirror and a Fresnel lens configured just before camera to correct aberrations and spot size. It is compact and portable at the expense of refraction loss. The Davies-Cotton design with F/2 can provide 16° full FOV and exhibits best off-axis performance of the conventional designs. But the obscuration of camera and focal length must be increased. For both designs, the optical spot size is designed to be similar as the dimension of selected size of pixels in the focal plane camera and angular resolution is superiors than expected.