Results from Cat and Prospects for the Vsa

We have produced an image of the microwave sky with 30 resolution in a 2 field using the Cosmic Anisotropy Telescope (CAT). Analysis of data taken at three frequencies near 15 GHz indicates that most of the signal is due to the CMB, with an equivalent broad-band power of ∆T/T = 1.9 −0.5 × 10 −5 at angular scales corresponding to multipoles l = 320– 500, and ∆T/T = 1.8 −0.5 × 10 −5 at l = 500–680. We are now building a more advanced instrument, the Very Small Array (VSA), which will cover the range l = 130–1800 with a sensitivity per resolution element of ∆T/T ∼ 10.