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THEMIS data handling

THEMIS data handling. Arturo López Ariste Alberto Sainz Dalda. THEMIS MTR mode. MTR: Multiline spectropolarimetry mode. Up to 10 spectral domains observed simultaneously from 4000 Å through 13000 Å Full freedom on scanning over the solar surface and on polarimetric modulation cycle

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THEMIS data handling

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  1. THEMIS data handling Arturo López Ariste Alberto Sainz Dalda

  2. THEMIS MTR mode MTR: Multiline spectropolarimetry mode Up to 10 spectral domains observed simultaneously from 4000 Å through 13000 Å Full freedom on scanning over the solar surface and on polarimetric modulation cycle ~1 Gbyte /hour data rate.

  3. Some bad experiences • On the telescope: • Observers cannot handle the raw data flow. • Up to 75% of the observers are not at hands with raw spectropolarimetry data • More than 50% of the observers come to THEMIS to “measure the magnetic field” and not Stokes parameters.

  4. Some bad experiences • On the telescope: • Observers cannot handle the raw data flow. • Up to 75% of the observers are not at hands with raw spectropolarimetry data • More than 50% of the observers come to THEMIS to “measure the magnetic field” and not Stokes parameters. • At BASS 2000: • Users are not interested in raw data • Users are not interested on Stokes parameters • Users want magnetic field maps • Users are not used to vector fields!

  5. What we did/are doing • Online data reduction code: SQUV • Quasi-automatic , quasi—real-time • Provides Stokes parameters from raw data • Handles all normal situations (above 80% success rate) • Ensures a nominal 10-3 polarimetric sensitivity. • Provides up to 10-4 at shared-risk policy

  6. What we did/are doing • Online data reduction code: SQUV • It is automatically launched by the telescope at the end of appropriate observing sequences • Can be downloaded for personal use under GNU-like license (www.themis.iac.es) • It is being implemented at BASS2000 for old data.

  7. Example

  8. What we did/are doing • Stokes analysis and inversion: • GUI-tools to check profiles and build maps • GUI-tools to invert (Fe I 630 nm line, Milne-Eddington) • GUI-tools to check inversions • GUI-tools to to analyze vector fields in observer’s and local frames and investigate azimuth ambiguity Online at the telescope, inversion launched by the acquisition system Downloadable under GNU-like license (www.themis.iac.es)

  9. PCA Inversion

  10. Some bad experiences • On the telescope: • Observers cannot handle the raw data flow. • Up to 75% of the observers are not at hands with raw spectropolarimetry data • More than 50% of the observers come to THEMIS to “measure the magnetic field” and not Stokes parameters. • At BASS 2000: • Users are not interested in raw data • Users are not interested on Stokes parameters • Users want magnetic field maps • Users are not used to vector fields!

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