Abstract
We have developed two redundant daytime star cameras to provide the fine
pointing solution for the balloon-borne submillimeter telescope, BLAST. The
cameras are capable of providing a reconstructed pointing solution with an
absolute accuracy < 5 arcseconds. They are sensitive to stars down to
magnitudes ~ 9 in daytime float conditions. Each camera combines a 1 megapixel
CCD with a 200 mm f/2 lens to image a 2 degree x 2.5 degree field of the sky.
The instruments are autonomous. An internal computer controls the temperature,
adjusts the focus, and determines a real-time pointing solution at 1 Hz. The
mechanical details and flight performance of these instruments are presented.
