Status of SX Requirements

The original requirements for the SX (circa 1995) are listed below along with an indication beside each requirement as to whether it has been met (Yes), not met (No) or not applicable any more (NA).  Other comments are added as necessary.

The science archive shall consist of:

  1. A science database that shall:
  2. a. Retain calibrated object catalogs (photometric CCD output) Yes
    b. Retain parameters from spectroscopic pipeline Yes
    c. Enhanced goal: provide ability to recalibrate object catalogs No
    d. Retain references to atlas images and extracted spectra Yes
    e. Provide ability to carry out manual target selection for certain target categories Yes
    f. Provide ability to carry out offline QA activities Yes
    g. Provide ability for SDSS scientists to extract subsets of retained data Yes
    h. Enhanced goal: Provide ability to retain scientist-derived data sets No
    i. Enhanced goal: Provide smooth transition to public distribution system No
  3. A set of files tracked by the science database Yes (tsObjc, tsField, fpAtlas, fpBin, psSpec, fpMask)
  4. A set of files not tracked by the science database Yes (all other files)


All primary science archive requirements have been met, with the exception of the enhanced goals.

I. Input to Science Archive

  1. Survey Definition
  2. a. A description of the North Imaging survey area  Yes
    b. Survey progress: A description of sky inserted into database to date  Yes
  3. Final Astrometric Calibration
  4. a. List of r' band calibration coefficients on a frame-by-frame basis Yes

    [TBD: Are position errors stored on an object-by-object basis?]
  5. Final Photometric Calibraton
  6. a. List of photometric calibration coefficients on a frame-by-frame basis Yes
  7. Merged Object Lists
  8. a. A list of calibrated objects and parameters from the Frames pipeline of photo Yes
    b. A list of object masks from the Frames pipeline of photo No (photo not providing masks, only bit flags), needs to be extracted (who, when?)

    [TBD: Do a and b provide all information about masked areas of sky?]
    c. Run and Field information. Might be needed for recalibrations Yes
    d. Star/Galaxy/QSO classifications Yes
    e. Enhanced goal: Cross-identifications to other catalogs No (wait till real mandate for this; FIRST, USNO, ROSAT incl.)
  9. Target Selection
  10. a. A list of all targetable objects with target selection categories No (target does not store this - to be changed)
    b. A list of all objects from a selected as targets with selection category Yes
    c. Tiling flags for all objects in b Yes (coming with schema for spectra)
    d. Reports for all targets selected manually No (target does not store this - to be changed)
  11. Spectroscopic Pipeline
  12. a. Redshifts and parameters of all targeted objects Yes
    b. Enhanced goal: Tile and plate information Yes

    [TBD: If a target has multiple spectra obtained, is there a need to assign one as a primary measurement?] NA
  13. Enhanced goal: Scientist derived catalogs No
  14. Enhanced goal: Other input catalogs No
  15. Separate files tracked from Science Database
  16. a. Atlas Images Yes (under construction)
    b. 1-D spectra Yes (under construction)
  17. Separate files not tracked or accessible from Science Archive
  18. a. Compressed pixel map
    b. Full corrected pixel map
    c. Corrected spectroscopic frames
    d. Unused data
  19. TBD: Southern Survey Yes (same as Northern)


All the basic requirements for Inputs have been met - the SX meets these requirements to the extent possible with the current inputs provided by the photo and spectro pipelines.  The enhanced goals have not been met.

II. Functional Goals

  1. User will be able to carry out efficient queries to locate objects over one or more ranges of following attributes:
  2. a. Longitude or latitude in several spherical coordinates
    i) J2000 Ra and Dec Yes
    ii) J1950 Ra and Dec Yes
    iii) Enhanced goal: Ra and Dec of arbitrary epoch No
    iv) Galactic coordinates Yes
    v) Survey Coordinates Yes
    vi) Any linear combination of the two coordinates Yes
    b. Radius within a give point of the sky Yes
    c. u' g' r' i' z' (One set of magnitudes per object) Yes
    d. Any linear combination of c. Yes
    e. Object radius (one per object) Yes
    f. Surface brightess formed by c and d Yes
    g. Star/Galaxy/QSO Classification flag Yes
    h. Object class (small/medium/big/mask) Yes
    i. Target Selection Category Yes (target flags)
    j. Spectrum available flag Yes (link exists?)
  3. User will be able to carry out queries on any retained object parameter (subject to implementation constraints) Yes
  4. Enhanced Goal: All calibrated quantities can be recomputed using improved astrometric and photometric calibrations. Queries can be performed on the recalibrated quantities Yes (in principle, with methods defined on objects)
  5. For all efficient queries, return an esimated number of objects to be located Yes
  6. For all located objects, users shall be able to specify an arbitrary subset of stored parameters to be returned (subject to implementation constraints) plus the following derived quantities: Yes
  7. a. Number of located objects Yes
    b. TBD: Extra parameters Yes (e.g. AVERAGE, MIN, MAX, STDDEV etc.)
  8. Users shall be able to perform the following functions:
  9. a. Efficient repeated queries [e.g, get all objects within each of 10,000 QSOs in my favorite catalog).] No
    b. Make simple plots, etc. of returned parameters (e.g., SMONGO) No, but can do with AEs
    c. Formulate new queries based on results of previous queries NA
    d. TBD: What else?


All the basic functional goals, with the exception of efficient repeated queries and the ability to make plots in the SX, have been met.  One of the two enhanced goals has been met.

III. Technical Goals

  1. User interface
  2. a. User interface shall be developed in a TCL/Tk/TclDp environment Yes
    b. User interface shall communicate with a query support layer via ASCII interface protocol Yes
    c. Data shall be returnable to files, sockets, or pipes. Returned data shall use binary machine independent format (FITS binary, ASCII if appropriate, TBD: FITS ASCII, other?) Yes
  3. Enhanced goal: Data shall be stored in a system providing industry-standard OSQL-like interface to enable use of commercial products to provide alternative view of the database Yes (Objy has SQL++)
  4. Distributability
  5. a. A master copy of all data shall be maintained (the Master Science Archive) Yes
    b. Capability shall be present to replicate all or part of the Master Science Archive as local databases at SDSS institutions. Replication may consist of:
    i) Science Database in its entirety Yes
    ii) All or part of separate files tracked by Science Database Yes
    iii) No capability shall be present to replicate an arbitrarily selected subset of the science database beyond that described by section 1.c of USER INTERFACE Yes
    iv) Replication of databases shall be possible on all SDSS supported platforms Yes
    d. No capability is required be present to replicate all or part of separate files not tracked by Science Database Yes
  6. Security
  7. a. Master Science Archive shall be protected against corruption by SDSS participant user Yes
    b. Master Science Archive shall be protected against unauthorized access Yes


All the technical goals have been met.

Peter Z. Kunszt, Ani R. Thakar,
Last Modified: Jul 11, 2000.