Reduced data available for public download
4 septembre 2017 ( maj : 24 mars 2021 ), par Nadège Meunier
Description of the data available in the public releases
The SPHERE-DC aims at providing a full reduction of all public SPHERE data. Given the huge amount of data, we spent several years developping a fully automatic pipeline that provide good reduction in most cases. It works well for typical SPHERE science cases (exoplanet/disc imaging, high contrast extended source) acquired in average and good observing conditions. However when dealing with poor or very variable observing conditions or less common science cases (notably low contrast extended source such as resolved solar system objects), the outputs provided by the SPHERE-DC might not be of paper-grade quality and need to be carefully checked before use in publications.
SPHERE-DC reduction in short
Our pipeline basic reduction draws on the ESO public pipeline supplemented by several IDL/Python routines improving the quality of the reduction and the ability to deal with poor/heterogeneous dataset. We also calibrate the data in wavelength, flux and astrometry and present the outputs of these basic reduction steps (’Level 1 data’) as 4D datacubes (x,y,nframes, lambda) as commonly used in high contrast imaging. We also propose a complete ADI and/or SDI reduction (’Level 2 data’) using several different algorithms from the SpeCal routine set (Galicher et al. 2018). The reduction is described in detail in our manual :
While we aim to provide in the future robust reductions for all SPHERE instruments modes, we started with most commonly used (IRDIS/IFS). See the table below to see the all modes supported at the moment.
| Instrument | Supported modes | Mode support in progress | Mode not supported yet |
|---|---|---|---|
| IFS | ALL modes, ADI/ASDI | – | – |
| IRDIS | Single and dual-band imaging ADI/ASDI | Polarimetry | LSS ; SAM |
| ZIMPOL | – | ALL modes (intensity and polarimetry) | – |
Since the mass reduction of all SPHERE public data is time and ressource consuming, we release reduced data ESO semester by ESO semester, as soon as each semester is fully reduced and the data quality has been checked.
| Reduced and available | Reduction in progress | Estimate of future releases | |
|---|---|---|---|
| Day time calibrations | All IRDIS/IFS existing calibs are available | Calibrations from yesterday | Automatically up to date with at most 48hrs delay |
| IRDIS/IFS ESO periods | SVT ; P95 ;P96,P97,P98,P99,P100 | P101,P102 | all public data |
| Corresponding dates | 2014-05-01 to 2018-03-31 | 2018-04-01 to 2019-03-31 | Up to 2020-03-31 |
| ZIMPOL reductions | No ZIMPOL data | P95 ; P96 ZIMPOL data | all public Zimpol data |
| Other comments | Some SVT and commissioning data not reduced | – | – |
DATA ACCESS :info here
ADI algorithms released
Level 2 data includes residual maps after ADI or ASDI processing. The used algorithm can be identified by the field “Reference” in the process brower (see FAQ) and in the directories after retrieval. They are :
NoADI : simple stacking of the master cubes
cADI : Classical Angular Differential Imaging (Marois et al. 2006, Lafrenière et al 2007)
TLOCI : Flavor of Angular Differential Imaging based on Locally Optimised Combination of Images (Marois et al .20011, Galicher et al 2018)
PCA : Flavor of Angular Differential Imaging based on Principal Component Analysis
On demand we can run
ASDI-PCA : For IFS data ; we run a PCA analysis using both the time and the spectral dimension to build the reference image which significantly increases the detection limits
We can use on demand others algorithms on you favourite dataset.
Please do not hesitate to contact us at sphere-dc-req at univ-grenoble-alpes.fr is you have any comment, specific needs or suggestions on the released data, or if you notice any issue. —
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