CRISPRED: A data pipeline for the CRISP imaging spectropolarimeter

TL;DR

CRISPRED is a comprehensive data pipeline that automates the processing of complex spectropolarimetric data from the CRISP instrument, enabling the production of science-ready data with improved calibration and alignment methods.

Contribution

It introduces new calibration and co-alignment methods specifically for Fabry-Perot spectropolarimeters and documents a complete pipeline for the CRISP instrument at SST.

Findings

Developed flat-fielding techniques for telecentric Fabry-Perot data

Implemented an accurate camera co-alignment approach

Streamlined data processing for high-resolution solar spectropolarimetry

Abstract

The production of science-ready data from major solar telescopes requires expertise beyond that of the typical observer. This is a consequence of the increasing complexity of instruments and observing sequences, which require calibrations and corrections for instrumental and seeing effects that are not only difficult to measure, but are also coupled in ways that require careful analysis in the design of the correction procedures. Modern space-based telescopes have data-processing pipelines capable of routinely producing well-characterized data products. High-resolution imaging spectropolarimeters at ground-based telescopes need similar data pipelines. We present new methods for flat-fielding spectropolarimetric data acquired with telecentric Fabry-Perot instruments and a new approach for accurate camera co-alignment for image restoration. We document a procedure that forms the basis of current state of the art processing of data from the CRISP imaging spectropolarimeter at the Swedish 1-m Solar Telescope (SST). By collecting, implementing, and testing a suite of computer programs, we have defined a data reduction pipeline for this instrument. This pipeline, CRISPRED, streamlines the process of making science-ready data. It is implemented and operated in IDL, with time-consuming steps delegated to C. CRISPRED will be the basis also for the data pipeline of the forthcoming CHROMIS instrument.