pan-starrs observational requirements specification
DESCRIPTION
Pan-STARRS observational requirements specification. Outline. Benchmark design specs Telescopes Detectors Pipeline Data products Precision goals Specification of observational requirements Format for input to science DWG. Pan-STARRS in a Nutshell. Who? - PowerPoint PPT PresentationTRANSCRIPT
Pan-STARRSobservational requirements
specification
Outline
• Benchmark design specs– Telescopes– Detectors– Pipeline– Data products– Precision goals
• Specification of observational requirements– Format for input to science DWG
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 A=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
Telescope specs
• 4 x 1.8-2m RC + WF corrector• 7 sq deg FOV• F/4 or ~m/arcsec• A = 4 x 13.5-15 m2 deg2
– MEGACAM, SUPRIMECAM ~ 8 m2 deg2
• Filters: BVRIZ, R+V (U?)• Dedicated follow up telescope?
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 -> 12m pitch• ~2s read out• ~3e read noise
– 2read = 0.1 2
sky @ t ~ 15 s (V+R)
The Orthogonal Transfer Array (OTA)
• A new paradigm in large imagers
OTCCD pixelstructure
Basic OTCCD cellOTA:
8x8 array of OTCCDs
OTCCD Array
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
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
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
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
Precision goals
• Photometry– ~1% absolute– Better relative
• Astrometry– Statistical: ~ 0”.07 (FWHM/0”.6)(5/SN)
• Floor at ~0”.003– Systematics: < 0”.10
• Coherent over ~10 arcmin
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
Observational Requirements Specification
• Fundamental parameters– Sky coverage – 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?
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)