Hinode Calibration for Precise Image Co-alignment between SOT and XRT (November 2006 -- April 2007)

TL;DR

This paper details the calibration process enabling precise co-alignment of images from the Hinode spacecraft's SOT and XRT instruments, achieving better than 1 arcsecond accuracy to study solar magnetic activity.

Contribution

It introduces a calibration method for accurate image co-alignment between SOT and XRT, validated through Mercury transit observations and regular measurements.

Findings

Achieved co-alignment accuracy better than 1 arcsecond

Validated calibration method using Mercury transit data

Confirmed stable and precise instrument alignment over time

Abstract

To understand the physical mechanisms for activity and heating in the solar atmosphere, the magnetic coupling from the photosphere to the corona is an important piece of information from the Hinode observations, and therefore precise positional alignment is required among the data acquired by different telescopes. The Hinode spacecraft and its onboard telescopes were developed to allow us to investigate magnetic coupling with co-alignment accuracy better than 1 arcsec. Using the Mercury transit observed on 8 November 2006 and co-alignment measurements regularly performed on a weekly basis, we have determined the information necessary for precise image co-alignment and have confirmed that co-alignment better than 1 arcsec can be realized between Solar Optical Telescope (SOT) and X-Ray Telescope (XRT) with our baseline co-alignment method. This paper presents results from the calibration for precise co-alignment of CCD images from SOT and XRT.