Solar Physics Division Meeting 2000, June 19-22
Session 2. Corona, Solar Wind, Flares, CMEs, Solar-stellar, Instrumentation, Other
Display, Chair: J. Krall, Monday-Thursday, June 19, 2000, 8:00am-6:00pm, Forum Ballroom

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[2.91] Instrumental Effects and their Removal from TRACE Images

T.D. Tarbell, R.N. Nightingale, T.R. Metcalf, Z.A. Frank (LMSAL), TRACE Team

TRACE raw images often show fine structures at such high contrast that compensation for instrumental effects is not necessary to study their morphology and evolution. Nevertheless, TRACE team members have gradually been developing the techniques and calibrations necessary to understand and (sometimes) remove the principal instrumental degradations. These degradations include CCD pedestal variation with temperature and time, flat-field response, CCD sensitivity loss varying with position and wavelength, electrical interference during CCD readout, permanent dim pixels, intermittent hot pixels, overall system point spread function, diffraction of EUV radiation by the front entrance filters, scattered light at off-limb pointings, tracks of electrons and protons from the radiation belts, and artifacts from JPEG compression of solar strucures and the above defects. Characterization and removal of some of these will be presented in the poster, such as the following. A deconvolution routine can partially compensate for the EUV diffraction, which is described in the adjacent poster by Frank et al. White light flat fields are derived using the Kuhn-Lin algorithm. CCD sensitivity degradation (presumably lumogen damage) is measured both from crude UV and EUV flat fields and from mission-long analysis of synoptic disk center images; combining these results with the WL flats yields flat fields at all wavelengths. Some information on scattered light and point spread functions are obtained from the August, 1999, eclipse observations and the Mercury transit. SSW routines for dealing with some of these degradations will be identified.

This work is supported by the TRACE project at LMSAL (contract NAS5-38099).

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