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WP7, Task 2. Server conversion libraries from spectra native format to IVOA SED format. Intent. The problem SSA allows for spectra in “native” FITS format a multitude of different conventions tools need to cope with all these conventions The solution
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WP7, Task 2 Server conversion libraries from spectra native format to IVOA SED format AIDA WP7, Task 2 Third Technology Forum, 16 March 2009, Strasbourg Bruno Rino
Intent • The problem • SSA allows for spectra in “native” FITS format • a multitude of different conventions • tools need to cope with all these conventions • The solution • convert “native” spectra to Spectrum DM, on the server-side • First step • use ESO non-raw spectra as samples AIDA WP7, Task 2 Third Technology Forum, 16 March 2009, Strasbourg Bruno Rino
Investigation (1) • ESO Spectra: Data • Flux • “1-d” image on primary HDU • naxis = 1, naxis1 = n • 1-row “2-d” image on primary HDU • naxis = 2, naxis1 = n, naxis2 = 1 • Wavelength • ( i - crpix1 ) * cdelt1 + crval1 • i = 1..n • No error information AIDA WP7, Task 2 Third Technology Forum, 16 March 2009, Strasbourg Bruno Rino
Investigation (2) • ESO Spectra: Metadata • Required for data transformation: • naxis • crpix1, cdelt1, crval1 • Essential • cunit1 (Wave unit), bunit (Flux unit) • multiple syntaxes (A, Angstrom, erg/cm2/s/A, erg/cm^2/A/sec, erg/cm**2/s/angstrom) • Spectrum DM compliance • metadata lives in a DB AIDA WP7, Task 2 Third Technology Forum, 16 March 2009, Strasbourg Bruno Rino
Status • Proof of concept: • Python transformation CGI • Input: • URL pointing to a 1d image; • Output: • SED recommended FITS (i.e., BINTABLE with 1 row for 1 spectrum); • Header currently copied over as is AIDA WP7, Task 2 Third Technology Forum, 16 March 2009, Strasbourg Bruno Rino
To do • Check whether erroneous metadata can be recognised and fixed automatically • Add SPECTRUM DM suggested keywords (Coverage, sampling, curation, etc.) • Massive test against all ESO reduced spectra • What other FITS conventions are out there? • AIDA_WP7T2@eurovo.org AIDA WP7, Task 2 Third Technology Forum, 16 March 2009, Strasbourg Bruno Rino