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Observations

We deconvolved two pairs of HST Planetary Camera F555W and F785LP filter images of the globular cluster NGC 6352. The image scale is approximately 0.04 arcsec/pixel. We preprocessed the images applying the A/D correction, bias and preflash subtraction, dark current and flat field corrections. For both chips #7 and #8, three 300-second F555W exposures and four 1000-second F785LP images were averaged using the IRAF imcombine task with cosmic ray rejection to produce separate F555W and F785LP master frames for each chip. These master frames were deconvolved with the iterative/recursive algorithm invoked with 3 recursion levels and 2 iterations at each level. Variation of the PSF across the images was accounted for by dividing the approximately 750750 images into nine 300300 overlapping sections and restoring each section independently with a PSF generated by the Tiny TIM software (Krist 1992) for the section center. The signal-to-noise ratio of the fainter stars in the deconvolved images was much improved over those in the originals. There were no artifacts in the images, and the residuals produced by the slight mismatch between the actual PSF and the PSF used in the restorations were smaller compared to the central stellar fluxes than the diffuse halos in the original data. As shown below, these residuals have only a minimal effect on photometry of the images.


rlw@sundog.stsci.edu
Fri Apr 15 17:32:27 EDT 1994