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Pan-STARRS: Wide Field Imaging System for Deep Sky Surveys

The Pan-STARRS project proposes a wide field imaging system with 4 telescopes and CCD detectors for repeated scans of the entire sky, providing deep cumulative digital images. The project aims to revolutionize wide-field imaging surveys and enable various scientific applications.

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Pan-STARRS: Wide Field Imaging System for Deep Sky Surveys

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  1. Panoramic Survey Telescopeand Rapid Response System Pan-STARRS Astro 735 PanSTARRS Seminar Wednesdays, 12:30-1:30 UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  2. Pan-STARRS • A proposal for a wide field imaging system: • 4 x 1.8m telescopes each with • 4 x 1Gpixel CCD detectors • Operation: • Repeated scans of entire sky • Unique time resolution capability • Deep cumulative digital images of the entire sky • Time-scale: ~5 years • Project cost: ~$50M • Funded by AFRL • Collaboration between IfA, MHPCC, Lincoln Lab, SAIC UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  3. A Renaissance in Wide-Field Imaging • Detector technology advances enabling a revolution in wide-field imaging surveys • CCDs are efficient and costs are falling • ~100Mpix cameras deployed on several 4-8m telescopes • Ifa leads the field • current state-of-the-art: • SUBARU/SUPRIME • CFHT/MEGACAM 300Mpix (fall 2002) • A  8 m2 deg2 • dedicated survey instruments • Examples SDSS, 2MASS, MACHO • 1 data product - many science applications • public access via www UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  4. The Decadal Review LSST • US Decadal Review proposed a 6.5m class “Large Synoptic Survey Telescope” as a high priority near term goal • map the visible sky to R~24 in 1 week • time resolution capability • very deep cumulative images • closely linked to the VO (Virtual Observatory) • LSST Science Goals: • galaxy clustering • weak lensing • transients, GRBs • stellar variability • killer asteroids • planet searches • galactic halo + disk • supernovae • brown dwarfs UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  5. Small vs Large Apertures • Why size matters: • small telescopes are cheaper for given collecting area • CCD costs scale with detector area (not Npixels) • Optimal design matches seeing to CCD resolution • rapid construction and low risk • diversity of operation modes • Low environmental impact • Scalable • Fast guiding for enhanced image quality ….. UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  6. The Pan-STARRS Proposal • 4 x 1.8m with 7.1 deg2 FOV • A = 8 x SUBARU/SUPRIME, CFHT/MEGACAM • Sensitivity • R+V filter: R=24@5-sigma in texp = 30s (FWHM / 0”.6)2 • 4x simultaneous imaging • survey ~2,800 deg2 per night  DR LSST specification • cumulative integrations: 180 nights  1.6mag fainter • all sky surveys in multiple bands to ~26 mag • deeper surveys: • 4hr integrations  ~4000 deg2/yr @ ~26.5mag • 100hr integrations  ~200 deg2/yr @ ~28mag • “pilot project” for LSST - but does most of the science UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  7. Wide Field Imaging Science Opportunities • Time domain astronomy • Transient objects • Moving objects • Variable objects • Static sky science • Enabled by stacking repeated scans to form a collection of ultra-deep static sky images UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  8. Inner Solar System Science • ~107 asteroids • Families • Orbit parameter space structure • ~104 near earth objects • Phase-space distribution • Hazardous asteroids • Comets UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  9. Asteroid Collision Hazard • Asteroid collision rate is well understood • Maximum hazard comes from ~1-2km size objects at threshold of global catastrophes • Current surveys are ~50% complete for such objects and will approach ~80% completeness • Residual hazard will be roughly equally split between km and sub-km size objects • 1/700 chance of 300m (1000MT) impact in the coming century • A survey that can reach V=24 will eliminate nearly all km-scale risk and > 80% of risk for 300m scale UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  10. Outer Solar System Science • Kuiper Belt Objects • Orbital distribution • Formation and evolution • Trans-Neptunian Objects • Interlopers on hyperbolic orbits UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  11. Parallax survey Complete s tellar census to 100pc Proper motions Formation history Other goals: Stellar variability Low mass stars Extra-solar planets Stars and the Galaxy UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  12. Cosmology – Weak Lensing • Total mass power spectrum P(k) to large scales • Test of inflation theory • Evolution of P(k) • Higher order statistics • Gravitational instability theory • Cluster mass function • Cosmological parameters • Geometric tests • World model UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  13. Cosmology - Supernovae • Hubble diagram • Dark energy equation of state w(z) • Cosmological parameters • Supernova physics • Star formation history UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  14. Other Cosmology Goals • Cosmological transients • Orphaned gamma ray burst statistics • Coalescing binaries • Large scale structure • Galaxy clustering statistics via photo-z • Clustering vs galaxy type • Low surface brightness galaxies • AGN • High redshift galaxies UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  15. Pan-STARRS Priority 1 Goals • PHO census • Detect majority of potentially hazardous objects of diameter >300m (roughly 1000MT impact energy) • Weak lensing • Mass power spectrum to very large scales • Evolution of P(k) • Cosmological parameters from • Mass function of clusters • Geometric tests • Supernovae • Probing the equation of state of the dark energy • Understanding the star formation history of the universe • GRB afterglows • Testing theories of formation of the most luminous objects in the Universe UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  16. Other Science Goals • Solar System census • Local solar neighborhood census • Galactic census • Large-scale structure • Extra galactic object detection and classification • Extra-solar planets • Other programs as described in PSDC-200-016-00 • Unanticipated discoveries UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  17. Pan-STARRS Observatory States and Modes Operational Survey Modes • Solar System (Ecliptic Plane) – used primarily to satisfy the observing requirements imposed by the PHO, NEO, MBA, KBO and other SS programs. • 3 – used primarily to satisfy the observing requirements of the WL, LSN census, and EG object detection & classification programs; primary cadence drivers are the LSN census (and other proper motion studies) • Medium-Deep – the SNe, LSS, and the EG object detection & classification programs; primary cadence driver being SNe • Ultra-Deep – EG object detection & classification and, to some extent, SNe programs • Object Variability/Auxiliary – mostly user-defined supporting programs such as stellar variability and the search for extra-solar planets UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  18. Science Goals  Survey System Requirements • All PS science programs benefit from • Large collecting area • Large field of view • Good image quality • Short (and therefore numerous) exposures • Photometric precision • Astrometric precision • At a detailed level, some distinctions emerge • The PHO census benefits particularly from astrometric precision and demands short exposure times • The supernova program places a particular premium on photometric precision • The weak lensing program requires good control of the image shape • The GRB program requires prompt processing of the image data • The priority 1 science goals span this space of requirements • If these goals can be met then most, if not all, other science goals can also be satisfied. UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  19. Pan-STARRS System Concept Above considerations lead to a system concept of a distributed array of 3 or more telescopes, each with a Gigapixel camera with a 3 degree FOV made up of arrays of arrays of OTA CCDs. • Set of small telescopes is cheaper than single large telescope of equivalent collecting area. C D  2.6 – 3, but A D² • Allows simultaneous imaging of nearly the same field by ≥ 3 cameras • Fills in gaps and dead cells • Unambiguous identification of artifacts (cosmic rays etc) • Array of arrays CCD design dramatically improves yield, reduces cost. • Produces a clean combined image at a given time stamp. • Image reduction of individual detector images is highly parallel • Must reduce data at very nearly the same rate that you take it, or processing will fall behind. • Data processing can be done by large cluster of pc processors. UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  20. System Top-Level Description Conceptual Design: Divide System into six Subsystem modules that have conceptually simple interfaces. • Telescopes (includes enclosure) (TEL) • Cameras (includes control software) (CAM) • Observatory, Telescope, and Instrument Software (OTIS) • Image Processing Pipeline (IPP) • Moving Object Processing System (MOPS) • Published Science Products System (PSPS) UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  21. Pan-STARRS Overview UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  22. Pan-STARRS Operations and Process Flow UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  23. Pan-STARRS Operations and Data Flow UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  24. Science Data Products • Instrumental catalogs • - Instrumental magnitudes, coordinates • - For precision astrometry/photometry • - Postage stamps for bright objects • Cumulative static sky images • - Signal + exposure maps • - Best + working + compressed intermediate saves • Static sky catalogs • - Includes time history of object magnitudes • Difference image detection stream • Recent (~1 month) source and difference images UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  25. Data Validation and Science Program Compliance • Image Quality Assessment • Image Science Validation • Schedule Assessment • Schedule Changes • User Feedback • Science Goals Modification • Science Program Modification • System Modification UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  26. Pan-STARRS External Data Products UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  27. Today lets talk about four: • Published Science Products System (PSPS) • Telescopes (includes enclosure) (TEL) • Cameras (includes control software) (CAM) • Image Processing Pipeline (IPP) UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  28. PSPS Conceptual Design Components UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  29. 88” site option UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  30. 88” Site Option UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  31. 88” Site Option UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  32. Haleakala UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  33. Haleakala High Altitude Observatory Site UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  34. Overview LURE Dome - To be Replaced by IceStorm Enclosure housing PS1 Telescope Service Building To be Refurbished LURE building To be Demolished (excavated to rock) MAGNUM Dome Currently being replaced by University of Tokyo (at increased height) UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  35. Completed Facility Series II IceStorm Enclosure Refurbished LURE Building New Access Stairs Completed facility is contained within envelope of existing building plan UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  36. Enclosure Overview (Perspective) Level 3 : Observing Floor Level 2 : Floor below Mirror Cart / Camera Cart Rails Service Balcony 1200mm wide Access Door to Level 1 : Equipment / Rack Room (door not shown) Access Stair Access Balcony Ground Level : Storage UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  37. Hoist Beam Support Building Plan Door Door M1 2.2m Roller Door to Ground Floor of Enclosure Camera Workshop Camera Mezzanine Floor Over UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  38. Telescope Block Diagram • Blue Lines show mechanical interfaces = internal • Red lines show control interfaces = external • Open circles = external control computers/processes • Open boxes = external subsystems • CC = Cassegrain Core • M1, M2 = Primary & Secondary mirrors • L1-L3 = Corrector Lenses • B1-B3 = Baffles UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  39. Optical Design UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  40. Detector design • Problem: need to reduce cost/pixel, decrease read times • Solution - array of arrays • Each 5x5cm device is a 8x8 grid of independently addressable cells • Increased yield • Multiplexed readout • Ameliorates effects of bright stars • Continuous monitoring of many guide stars across focal plane UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  41. OTA Package UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  42. Gigapixel camera focal plane UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  43. Pixel structure OTA: 8x8 Array of Cells Independently Addressable Cell Orthogonal Transfer Technology • Conventional “3-phase” devices clock charge in 1 direction. • Adding a 4th gate per pixel allows clocking in 2-D • On chip fast guiding - guide out motions arising from first ~100m of atmosphere UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  44. OTCCDs Work M13 I band 300 sec With OT tracking Telescope guiding only 0.45" FWHM psf 0.59" FWHM psf 7 Hz frame rate UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  45. Typical Sequenced Readout • Open Shutter • Acquire • ~1 sec integration, readout ~0.5sec • Pixelserver determines ~5 guide objects in 5 cells per OTA • Guide + Integration • ~5 guide cell subarray readout at 10-30Hz (<100Hz) • Pixelserver centroids and determines guide subarray position • Pixelserver also computes OT parallel shift patterns for remaining cell • Expected Itimes Nominal 10s of seconds • Max ~1000sec • Min ~shutter speed/setup • Apply OT parallel shift clocks (~10usec each) • Delay ~50msec • Close shutter and Readout < 5 sec UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  46. Image Acquisition & Camera Operations UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  47. OTA Input and Control • Sequenced readout • Guide rates 10-30Hz • Nominal guide patch 10 arcsec patch = ~32 X 32 pixels ( 0.3 arcsec/pixel ) 10msec/1024 pixels = 9.77 μsec/pixel, max speed clock + signal condition + ADC + buffer • Centroid and shift calculation time + Change clock patterns, latency goal = 2msec • Clocking pattern time resolution ~10nsec UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  48. OTA Output • 100K e- well and expected 4e- noise at 1 MHz • 2e- noise goal at 100 kHz (guiding) • ADC bit resolution – approx two bits on the noise 100k / 4 = 25K X 2 = 50K resolution wanted (16 bits = 64K ( > 14bits)) • Image memory OTA 4096 x 4096 pixels = 16M pixels = 32MBytes (16 bit resolution) 8 x 8 focal plane = 1Gpixel = 2Gbytes (16bit) • Data buffering and storage Unless data transport is real time, minimum storage is 2Gbytes 4Gbytes double buffered. UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

  49. UNIVERSITY OF HAWAII INSTITUTE FOR ASTRONOMY Approved for Public Release - Distribution is Unlimited

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