Co-aligning EIS and SOT data#

This is not a definitive guide to co-aligning EIS and SOT data, but instead summarizes some methods that have been used in the literature.

O VI, MDI and SOT#

Mariska & Muglach (2010, ApJ, 713, 573) noted that a raster scan obtained in the EIS O VI 184.12 emission line showed similar structures to a MDI magnetogram, and so the two images were cross-correlated. The MDI image was then cross-correlated with the longitudinal component of a SOT SP map

Using TRACE#

TRACE data have been used to help co-align Hinode data by Brooks et al. (2010, ApJ, 720, 1380) and De Pontieu et al. (2009, ApJ, 701, L1).

Brooks et al. (2010, ApJ, 720, 1380) give a detailed account of how a SOT SP scan was co-aligned with TRACE 1600 filter data. The 1600 filter image from TRACE was co-aligned with the longitudinal magnetic (non-directional) component of the SP scan. Note that a rotation, magnification and translation was necessary to obtain a good co-alignement. These authors did not co-align TRACE with EIS.

De Pontieu et al. (2009, ApJ, 701, L1) co-aligned EIS data with SOT Ca II. They made use of a TRACE chromospheric channel (1600?) which was co-aligned with Ca II. The TRACE coronal images (from the EUV channels) were then co-aligned with an EIS coronal line. The offsets of the TRACE EUV channels relative to the white channel are known, and so the EIS pointing could be related to the SOT Ca II pointing. The authors estimate an accuracy of 2" for this work.