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Session 36 - Solar Activity.
Display session, Tuesday, June 11
Tripp Commons,

[36.14] Photometry of Restored Full-Disk Solar Images

S. R. Walton, D. G. Preminger (SFO/CSUN), C. G. Toner (NSO)

The San Fernando Observatory (SFO) Cartesian Full Disk Telescope (CFDT) has been taking full-disk 512 square photometric images of the Sun through a 100Å\ bandpass red filter since 1985, and through a 10Å\ bandpass K-line filter since 1989. We have recently begun a project to attempt to remove the effects of atmospheric blurring and scattered light on the photometry of these images. Specifically, we are fitting the convolution of a limb darkening profile expansion and a model point spread function (PSF) to the radial profiles of SFO CFDT images, using a technique similar to that of Toner and Jeffries (Ap. J. 1996, submitted) to remove the PSF from the images. The blurring-free limb darkening profile is the sum of an expansion in orthogonal (Legendre) polynomials, and the PSF model is the sum of three Gaussian components plus a Lorentzian, normalized so that its integral over the sky is unity. Tests with artificially generated images with sunspots show that we can recover the sunspot photometric quantities with excellent results. Comparison of the original and restored photometry from eight actual red images taken hourly also show that correlations between the PSF and the photometry disappear after the restoration. We have been less successful at recovery of facular photometry in the K line images, and are continuing to investigate this. We will present details of our fitting procedure and results. This project was partly supported by NSF Grant ATM-9115111 and NASA grant NAGW-3017.

Program listing for Tuesday