1 / 19

OmegaCAM: The 16k x 16k Survey Camera for the VST

OmegaCAM: The 16k x 16k Survey Camera for the VST. Calibration, Data Analysis Strategy and Software. Erik R. Deul Konrad Kuijken Edwin A. Valentijn. People involved. The Netherlands Kapteyn Institute : J-W. Pel, K. Begeman, D.R. Boxhoorn, E. Valentijn, K. Kuijken

brit
Download Presentation

OmegaCAM: The 16k x 16k Survey Camera for the VST

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript


  1. OmegaCAM: The 16k x 16k Survey Camera for the VST Calibration, Data Analysis Strategy and Software Erik R. Deul Konrad Kuijken Edwin A. Valentijn

  2. People involved • The Netherlands Kapteyn Institute: J-W. Pel, K. Begeman, D.R. Boxhoorn, E. Valentijn, K. Kuijken Sterrewacht Leiden: R. Rengelink, E.R. Deul • Germany Universitäts-Sternwarte München: R. Bender, L. Greggio, R. Häfner, U. Hopp, H. Kravkar, W. Mitsch, B. Muschielok, M. Neeser, R. Saglia Universitäts-Sternwarte Göttingen: R. Harke, H. Nicklas, W. Wellem Sternwarte der Universität Bonn: K. Reif • Italy Astronomical Observatory of Capodimonte - Napoli: E. Cascone Osservatorio Astronomico di Padova: A. Baruffolo, E. Cappellaro, E. V. Held, H. Nazaryan, G. Piotto, H. Navarsadyan, L. Rizzi • ESO D. Baade, A. Balestra, J-L. Beckers, C. Cavadore, C. Cumani, F. Christen, S. D'Odorico, S. Deiries, N. Devillard, C. Geimer, N. Haddad, G. Hess, J. Hess, O. Iwert, H. Kotzlowski, J-L Lizon, A. Longinotti, W. Nees, A. Renzini, J. Reyes Moreno, G. Sikkema, M. Tarenghi SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  3. Detectors • Science array 1 x 1 degree, 32 CCDs • 15 mm pixels – 0.21 arcsec/pixel • Marconi (former EEV) 2k x 4k • 16k x 16k pixels • Auxiliary CCD’s – 4 CCDs • For guiding • Image analysis SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  4. Filters More details see Harald Nicklas [4836-34] • Primary set • Sloan u’, g’, r’, i’, z’ • Johnson B, V • Narrow-band e.g. Ha up to 8000 km/s • Composite u’,B,V,i’ in four quadrants • User filter SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  5. VST construction see [4836-09] Mancini Details instrument control see [4848-10] Baruffolo

  6. Wide Field Imaging Science • Provide targets for VLT • 2/3 of time through ESO’s OPC • Individual programs • Supernovae, Lensing, Kuiper belt objects, Gamma ray, bursts, Microlensing, Brown dwarfs, High proper motion objects, Galactic halo objects, Quasars, AGNs • Sky Surveys • Long term archival research (10 yr mission) • Science Cases • Finding exceptional single, rare objects • Statistics on large samples of objects SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  7. Large Data Volume • Handling of the data is non-trivial • Pipeline data reduction • Calibration and re-calibration • Image comparisons and combinations • Working with source lists • Visualization } ESO compliant • Wide-field imaging instruments, vast amounts of data • E.g.: VST = Southern sky (30 min exp, 300 nights/y) in 3 years. Large amount of data! 100 Tbyte • Science can only be archive-based SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  8. Concepts for solution • Environment that provides systematic and controlled • Access to all raw and calibration data • Execution and modification reduction/calibration pipelines • Execution of source extraction algorithms • Archiving reduced data and source lists, or regenerates these dynamically • Can be federated to link different data centers • Dynamical archive continuously grows, can be used for • small or large science projects • generating and checking calibration data • exchanging methods, scripts and configuration • Key functionality • Link back from source data to the original raw pixel data and calibration files SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  9. How to use this • Deep multi-color fields • No need to take all data in one campaign • Combine data of particular quality, assess results • Select sources, visualize interesting ones, … • 1-in-1,000,000 events spurious or not? • Large homogeneous surveys • E.g. weak lensing maps, cluster searches, star counts • Variability (source list- or pixel based) • Proper motions (asteroids, nearby stars) • Flux variations • Monitor instrument (calibration files) • Planning observations • View quality of existing data • Build on what already exists, add more filters, more exposure time, better seeing, … SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  10. Solution • Procedurizing • Data taking at telescope for both science and calibration data • Full integration with data reduction • Design • Data model (classes) defined for data reduction and calibration • View pipeline as an administrative problem SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  11. Observing Modes • Dithermatching max. gap between arrays ~400 pixels • N pointings (N=5 is standard) • nearly cover all gaps in focal plane and maximizes sky coverage • the context map will be very complex • couple the photometry among individual CCDs. • Jittermatching the smallest gaps in CCDs ~5 pixels • optimizes for maximumhomogeneity of the context map • observationsfor which the wide CCD gaps are not critical • all data from single sky pixel originates from single chip • Stare reobserving fixed pointing positions multiple times • main workhorse monitoring instrumentand optical transients. • SSO observing Solar System objects • non-siderial tracking and the auto guiding switched off. SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  12. Observing Strategies • Standard • Single observations (one observing block) • Deep • Long, multiple integrations • Selected atmospheric conditions • Several nights • Frequent • Monitors same field • Timescales from minutes to months (overriding) • Mosaïc • Maps areas of sky > 1o SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  13. Calibration procedures Sanity checks Image pipeline Source pipeline Calibration procedures Quality control SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  14. Science Observations Bias pipeline Source pipeline Flatfield pipeline Photometric pipeline Image pipeline SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  15. Monitoring Photometric Calibration SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  16. Share the load • Processing • Hardware • Beowulf processors – 32 (most cases) • Multi Terabyte disks (10 – 100) • Data reduction • Derive calibration • Run image pipeline (1 Mpx/s) • Archiving • Storage • Images (100’s Tbyte), Calibration files (10 Tbyte) • Source parameters (1-10 Tbyte) • Federate (network speed) • 5 Mb/s (24 hours/day) full replication • 200 Mb/s no replication, on-the-fly retrieval SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  17. Contents of federation • Raw data • Observed images • Ancillary information • Calibration results • Calibration files time stamped • Reduced images • Single observation • Coadded images • Software • Methods (pipelines) for processing calibration • Configuration files • Source lists – catalogues • Extracted source information • Associated among different data objects SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  18. Concepts of federation • Federation maintained by a single database • Full history tracking • of all input that went into result • providing on-the fly reprocessing • Dynamical archive - Context as object attributes • Project: Calibration, Science, Survey, Personal • Owner: Pipeline, Developer, User • Strategy: Standard, Deep, Freq (monitoring), Mosaïc • Mode: Stare, Jitter, Dither, SSO • Time: Time stamping • Software standards • Classes/data model/procedures • 00 – inheritance/ persistency • Python scripts/ c-libraries SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

  19. Schedule • Hardware • Dome/Telescope erected at location • Camera on telescope Q1 2004 • First run: Jan 2004 • Second run: Mar 2004 • Software • Design – review Q2 2002- Done • Basic operations – Q4 2003 • Evaluate and prepare for mass production 2004 • Qualify and populate 2005 • Deliver survey system – satellites SPIE Conference [4836] Survey and Other Telescopes Technologies and Discoveries

More Related