COSTAR phase I alignment description

摘要

Abstract: The corrective optics space telescope axial replacement (COSTAR) configuration contains mechanisms in each science instrument channel that allow for on-orbit correction for image plane focus and for lateral and axial mapping of the Hubble Space Telescope (HST) primary mirror onto the aspheric corrector mirrors. The optical alignment of the COSTAR optics is accomplished in two phases. In Phase I, the mirror bezel tilts and lateral positions are determined through the use of surrogate flat mirrors with the mechanism's positions held at the mid-range of their travel. The Phase I alignment is followed by Phase II interferometric optimization of all five optical channels. At the conclusion of the Phase I alignment, the optics are positioned accurately enough to allow simultaneous correction of most channels on orbit through the use of the mechanism compensation and telescope fine-pointing control. Individual mirror positions and orientations are determined through the use of alignment telescopes, theodolites, alignment lasers, and reference fiducials incorporated into the COSTAR Alignment System (CAS). !0