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#
De Pontieu et al. (2009, ApJ, 701, L1) co-aligned EIS data with SOT Ca II. They made use of TRACE, which had a white light channel that could be 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.