Pan-STARRS observational requirements specification

1. Pan-STARRSobservational requirements specification

2. Outline • Benchmark design specs • Telescopes • Detectors • Pipeline • Data products • Precision goals • Specification of observational requirements • Format for input to science DWG

3. Pan-STARRS in a Nutshell • Who? • IfA - detectors, pipelines, science, site; MHPCC - data processing; SAIC - massive databases; Lincoln Lab - detectors • What? • Dedicated wide field optical survey AW=54 m2 deg2 • “pilot project” for LSST • How? • Funded by AFRL • 1st year (design development) funded - 2nd year funding in place - total system cost ~$40M • When? • To be operational in 2006

4. Telescope specs • 4 x 1.8-2m RC + WF corrector • 7 sq deg FOV • F/4 or ~36mm/arcsec • AW = 4 x 13.5-15 m2 deg2 • MEGACAM, SUPRIMECAM ~ 8 m2 deg2 • Filters: BVRIZ, R+V (U?) • Dedicated follow up telescope?

5. Detectors • Array of arrays • 4 x (8 x 8) x (8 x 8) x (512 x 512) = 4 x 1Bn pixels • OTCCD • 0”.3 pixels -> 12mm pitch • ~2s read out • ~3e read noise • s2read = 0.1 s2sky @ t ~ 15 s (V+R)

6. The Orthogonal Transfer Array (OTA) • A new paradigm in large imagers OTCCD pixel structure OTA: 8x8 array of OTCCDs Basic OTCCD cell

7. OTCCD Array

8. Electronics – Signal Chain • SDSU dual channel video board • 2 channels • 150 kpixel/sec • CDS, 16 bit ADC • 15 W power • Analog Devices 9826 • 3 channels (RGB) • 15 Mpixel/sec • CDS, 16 bit ADC • 250 mW power

9. Operation mode options • Simultaneous • 4 telescopes observe the same field • 7 sq deg => ~ 6000 sq deg / night @ 30s integration • Independent • 28 sq deg • Poorer rejection of cosmic ray and other backgrounds

10. The pipeline • Image acquisition • Flat fielding/sky subtraction/photo calibration • Registration • Warping to sky coordinates • 0”.15-0”.2 sampling • Stacking/cosmic ray rejection • Convolution with PSF (rotated) • Differencing • Accumulation

11. Data products • Cumulative sky images (BVRIZ…) • 0”.15-0”.2 sampling • Catalogs • Difference images • High resolution real-time stream • Lossy compressed -> archive • Transient catalogs • Point source ML fits etc

12. Precision goals • Photometry • ~1% absolute • Better relative • Astrometry • Statistical: s ~ 0”.07 (FWHM/0”.6)(5/SN) • Floor at ~0”.003 • Systematics: < 0”.10 • Coherent over ~10 arcmin

13. Performance summary • Sensitivity (assuming 0.6” seeing) • T(R=24) = 58s • T(V=24.4) = 67s • T(R+V) = 31s • 30s exposure -> 6000 sq deg / night • Sky noise • 7e/s/pixel from sky (R+V) • Read noise ~2-3e is negligible for t >~ 20s • Astrometry • Sigma=0”.07 (FWHM/0”.6) / (SN/5) • Systematics limited by atmosphere

14. Observational Requirements Specification • Fundamental parameters • Sky coverage W • Depth/integration time tint • Repeat visit cadence requirements (if any) • Filter requirements • Other requirements • Need for follow up? • Need for archival image data? • Time criticality? • Simultaneous multi-passband imaging?

15. Inputs to science design working group: • Science case: • Science objectives • Why will this be interesting in 2006-2010? • Requirements for optimal performance • I.e. what if Pan-STARRS were used exclusively for this task • Minimum requirements • Filters, integration times, follow up needs etc. • External requirements (if any)