Lessons learned from the optics and focal plane alignment of a wide field of view RC telescope

Medium-sized Aperture Camera (MAC) is the main payload for Earth observation satellite RazakSAT to be launched at the end of 2005. The flight model has been recently assembled and tested. The 300 mm diameter Cassegrain telescope optics and the focal plane assembly for a space camera have been aligned. Topics discussed in this paper include the lessons learned from the optics alignment and assembly of the telescope and the focal plane. A computer-aided alignment method was used for the alignment of the relatively wide field of view (+/-1 deg) telescope. RMS wavefront error measurement environment was found to be more critical than previously experienced, and the importance of the initial alignment is discussed. System modulation transfer function (MTF) was used as the figure-of-merit for the alignment of the focal plane assembly with linear CCD detectors. MTF was measured by a knife-edge scanning technique using a dedicated 450 mm diameter collimator with diffraction-limited performance.