The challenge of retrieving ready-for-science data from ground-based solar observations. Getting the most out of your data  


We have prepared a map of Freiburg containing useful information like, e.g., the location of the workshop venue (Katholische Akademie Freiburg) and a selection of restaurants and cafeterias around downtown.

The CASSDA team is looking forward to meeting you all soon!

Important Dates


Deadline for hotel room reservation has been moved to: 6 January, 2014.

The workshop is taking place from 18-20 February, 2014.

There will be an extra session on 'Stray light contamination' on the morning of February 21, 2014, taking place at KIS. If you are interested in joining this session, please contact us (cassda@leibniz-kis.de). And in that case, let us know if we should extend your room reservation.

Workshop venue and accomodation

The workshop is taking place at the Katholische Akademie (KA) in Freiburg.

We have booked rooms for most of you at the KA. The room reservation can be cancelled/modified under these conditions:

  • 40 days before arrival free of charge
  • 40 to 20 days before arrival 30% of costs
  • 20 to 10 days before arrival 60% of costs
  • 10 to 1 days before arrival 90% of costs
  • 1 to 0 days before arrival 100% of costs 

List of participants (INPO)

  • Manolo Collados (IAC)
  • Arturo López Ariste (THEMIS)
  • Bernard Gelly (THEMIS)
  • Bob Bentley (UCL)
  • Daniel Müller (ESA)
  • Bernhard Fleck (ESA)
  • Stein Vidar Haugan (UiO)
  • Friedrich Wöger (NSO)
  • Frank Hill (NSO)
  • Kevin Reardon (NSO)
  • Christian Beck (NSO)
  • Tom Berger (NSO)
  • David Elmore (NSO)
  • Alfred de Wjin (HAO)
  • Rebecca Centeno (HAO)
  • Andreas Lagg (MPS)
  • Alex Feller (MPS)
  • Sanja Danilovic (MPS)
  • Michiel van Noort (MPS)
  • Franz Kneer (IAG)
  • Julián Blanco (Valencia University)
  • Torsten Waldmann
  • Jaime de la Cruz (SU)
  • Mats Löfdahl (SU)
  • Göran Scharmer (SU)
  • Jan Jurcak (ASU)
  • Marco Stangalini (INAF)
  • Fabrizio Giorgi (INAF)
  • Sara Esteban Pozuelo (IAA)
  • Reza Rezaei (KIS)
  • Rolf Schlichenmaier (KIS)
  • Hans-Peter Doerr (KIS)
  • Sebastian Hoch (KIS)
  • Juan Manuel Borrero (KIS)
  • Joachim Staiger (KIS)
  • Wolfgang Schmidt (KIS)
  • Markus Roth (KIS)
  • Thomas Berkefeld (KIS)
  • Dirk Soltau (KIS)
  • Oskar von der Lühe (KIS)
  • Svetlana Berdyugina (KIS)
  • Daniel Gisler (KIS)
  • Catherine Fischer (CASSDA, KIS)
  • Christian Bethge (CASSDA, KIS)
  • Johannes Löhner-Böttcher (CASSDA, KIS)
  • Nazaret Bello González (CASSDA, KIS)

Workshop Program


Welcome (S. Berdyugina)

SOLARNET Introduction (M. Collados)
CASSDA/Workshop Introduction (N. Bello González)

SESSION 1 Image reconstruction - 'What your pixel doesn't want to tell you' (Chair: R. Schlichenmaier)

S 1.1     Introduction   KISIP - a short overview (F. Wöger)

S 1.2     Introduction   MOMFBD - a short overview (M. Löfdahl)

S 1.3     Introduction   Longtime exposure image reconstruction (T. Waldmann)


S 1.4    Introduction   Application of reconstruction techniques on imaging and imaging spectro-polarimetric data (Ch. Beck)

S 1.5     Discussion      Comparison of data samples: Speckle techniques vs. MOMFBD vs Longtime exposure: Intensity contrast, artifacts, power spectrum. Comparison of physical parameters. Difficulties in PSF retrieval and noise issues (Discussion leader -DL: M. Löfdahl)

S 1.6    Introduction     Reconstruction with phase diversity using analytical PSFs (A. López Ariste)


SESSION 2 Data dissemination - 'Getting your data to the solar community' (Chair: C. Fischer)

S 2.1    Review talk   Lessons learnt in providing integrated access to space- and ground-based observations (R. Bentley)

S 2.2    Introduction   Visualization tools (j)Helioviewer and event searching (HEK) (D. Müller) 

S 2.3    Discussion      Why is some data more used than other? How to promote your data archive or VO? How to promote your instrument? What makes data accessible? (DL: S. Haugan)

Reception at KIS


SESSION 3: Data calibration I - 'Of artifacts, noise, λ-wiggles and other unwanted guests' (Chair: W. Schmidt)

S 3.1    Introduction    Slit spectrographs and their issues (D. Elmore)

S 3.2    Introduction    FPI systems, wavelength shifts & lambda fluctuations (F. Kneer)

S 3.3    Discussion      Cavity errors and instrumental wavelength shifts: CRISP, TESOS and IBIS cases. How to deal with them (DL: O. von der Lühe)


S 3.4    Introduction    Stray light contamination (A. Feller)

S 3.5    Discussion      Stray light, what is it? Can we measure it? Can we correct for it? (DL: A. Feller)


SESSION 4: Data calibration II - 'Tidying up your Stokes profiles' (Chair: R. Rezaei)

S 4.1     Introduction    Instrumental polarisation calibration: measuring the effect of telescope crosstalk and crosstalk correction, polarization fringes (M. Collados)

S 4.2    Discussion      Which polarimetric sensitivity is actually required? SNR or how to measure the weak field. Polarimetric efficiencies: better Q, U signal at expenses of V? Spectral resolution vs SNR, is there an optimum trade-off? (DL: M. Collados)

S 4.3    Introduction   Fringe removal with Compressed-sensing (A. López Ariste)

S 4.4    Introduction    Spatially coupled inversion of spectro-polarimetric data (M. van Noort)


S 4.5    Introduction    PCA-filtered deconvolution (A. López Ariste)

S 4.6    Discussion      Are these methods (S 4.4 and S 4.5) applicable to ground based observations? How much data-postprocessing can your data take? How can we deal with noise issues? (DL: A. López Ariste)

SESSION 5: On the horizon (Chair: O. von der Lühe) 

S 5.1    Introduction    Fast-SP (A. Feller), LARS (HP Doerr), HELLRIDE/CARMA (J. Staiger)

S 5.2    Discussion      Expectations for new instruments, e.g., VTF (DL: W. Schmidt)

Social Event


SESSION 6: Data pipelines I -  'Concepts and codes. Towards an automated data handling'

S 6.1    Introduction    Challenges for integrated data centers for ground-based solar data (K. Reardon)

S 6.2    Introduction    Existing packages:  CRISP (J. de la Cruz), CASSDA GUI (J. Löhner-Böttcher) & THEMIS packages (B. Gelly)


S 6.3    Introduction    CASSDA - driven by the needs of the solar ground based community (C. Fischer)

S 6.4    Discussion      Unifying existing codes. Keeping it general and avoiding duplicity. Should there be a software pool for ground-based observatories where one can load instrument specific routines?  (DL: B. Fleck)


SESSION 7: Data pipelines II - 'Data format and metadata standards, data level product  - 'Providing science-ready data in a comprehensible and unified form' (Chair: M. Roth)

S 7.1    Introduction    Current data standards and formats (F. Hill)

S 7.2    Discussion      Standardised data headers, (WCS) image coordinates, data quality for ground observations (DL: H-P Doerr)


S 7.3    Introduction    The Community Spectro-Polarimetric Analysis Center - CSAC (R. Centeno)

S 7.4    Discussion      Which data level should be provided to the community? (DL: R. Centeno)

Summary. Outlook (N. Bello González)

EXTRA SESSION: Stray light contamination

On Friday, February 21, we had an extra session at KIS on 'Stray light contamination' (continuation of Session S3.4)


G. Scharmer: What is the source of straylight in SST/CRISP data?

D. Soltau: Stray light. Where has all the contrast gone?

F. Kneer: Parasitic Light

R. Schlichenmaier: Some issues on stray light in GREGOR