What is Pan-STARRS?

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What is Pan-STARRS?

• Telescopes
• 4 x 1.8m
• 7 square degree FOV
• possible sites on Mauna Kea and Haleakala
• Operation mode
• simultaneous imaging of the same field for
  transient/moving object detection
• broad band optical imaging
• multiple survey modes

• Detectors
• 1Bn pixels per camera
• array of arrays
• 0.3 pixels
• few second readout
• lt5e- read-noise
• Data-Processing System
• Core pipeline will generate
• snapshot images
• difference/summed images
• basic catalogs
• NEO system

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Performance Summary

• Sensitivity (assuming 0.6 seeing)
• T(R24) 58s
• T(V24.4) 67s
• T(RV24) 31s
• 30s exposure -gt 6000 sq deg / night
• Sky noise
• 7e/s/pixel from sky (RV)
• Read noise 2-3e is negligible for t gt 20s
• Astrometry
• Sigma0.07 (FWHM/0.6) / (SN/5)
• Systematics limited by atmosphere

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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
• Fast guiding for enhanced image quality
• Low environmental impact

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Trends

• Future dominated by detector improvements

• Moores Law growth in CCD capabilities
• Gigapixel arrays on the horizon
• Improvements in computing and storage will
  track growth in data volume
• Investment in software is critical, and
  growing

Total area of 3m telescopes in the world in m2,
total number of CCD pixels in Megapix, as a
function of time. Growth over 25 years is a
factor of 30 in glass, 3000 in pixels.
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D 1.5m
D 8m
D4m

• For (D 4 r0) 35 of light is in a single
  bright speckle
• guiding at 10Hz gives PSF with diffraction
  limited core
• tip-tilt on large apertures is relatively
  ineffective

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Detector Details Orthogonal Transfer

• Orthogonal Transfer
• remove image motion
• high speed (few usec)

Normal guiding (0.73)
OT tracking (0.50)
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File C\ZEMAX\panstars\PS-prelim-9.ZMX Title
Pan-STARRS preliminary design review Date TUE
DEC 9 2003 SURFACE DATA SUMMARY Surf Comment
Radius Thickness Glass Diameter Conic
r2 r4 r6 6 Primary -7850
-2257.85 MIRROR 1800 -1.52934
2.24e-21 7 Secondary -6658 2057.85
MIRROR 900 -18.6695
4.68e-19 9 LENS-1A 994.5 60
F_SILICA 640 0 10 LENS-1B 1732.7
10 640 0 11 LENS-2A
801.7 45 F_SILICA 620 0 12
LENS-2B 540.0 815 620
0 13 FILTER-A Infin 20 F_SILICA
530 0 14 FILTER-B Infin 100
530 0 15 LENS-3A -1928.5
50 F_SILICA 520 0
4.02e-10 1.51e-15 16 LENS-3B -1790.1
198.07 520 0 IMA CCD-ARRAY
Infin 500 0
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Performance in U and Y

• Optical Performance deteriorates at extreme ends
  of the optical region
• Using a curved filter helps by giving extra
  refractive power

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Distortion
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Ghost Image Analysis

• Pupil ghosts
• Image ghosts

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Fabrication of the aspheric Optics

• The asphericity of the mirrors is within
  established fabrication capability.
• Dewar window is an order of magnitude less
  aspheric than the Sloan window ( 1 mm vs. 8mm)

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Listing of surface sag File C\ZEMAX\panstars\P
S-prelim-9.ZMX Title Pan-STARRS rounded Date
MON NOV 24 2003 Units are Millimeters. Semi
diameter of surface 6 9.000000E002. Best Fit
Sphere curvature -1.269040E-004. Best Fit
Sphere radius -7.879973E003. Best Fit
Sphere residual 2.979204E-002. (rms)
Y-coord Sag BFS Sag
Deviation Remove 0.0E000 0.00000E000
0.00000E000 0.00000E000 6.31004E-002
5.0E001 -1.59234E-001 -1.58631E-001
6.03222E-004 6.37036E-002 1.0E002
-6.36929E-001 -6.34545E-001 2.38346E-003
6.54839E-002 1.5E002 -1.43305E000
-1.42779E000 5.25245E-003 6.83528E-002
2.0E002 -2.54755E000 -2.53848E000
9.06295E-003 7.21633E-002 2.5E002
-3.98035E000 -3.96674E000 1.36087E-002
7.67091E-002 3.0E002 -5.73137E000
-5.71275E000 1.86243E-002 8.17247E-002
3.5E002 -7.80049E000 -7.77670E000
2.37849E-002 8.68854E-002 4.0E002
-1.01875E001 -1.01588E001 2.87063E-002
9.18067E-002 4.5E002 -1.28924E001
-1.28595E001 3.29439E-002 9.60444E-002
5.0E002 -1.59149E001 -1.58790E001
3.59936E-002 9.90940E-002 5.5E002
-1.92549E001 -1.92176E001 3.72901E-002
1.00390E-001 6.0E002 -2.29121E001
-2.28759E001 3.62077E-002 9.93081E-002
6.5E002 -2.68862E001 -2.68542E001
3.20589E-002 9.51593E-002 7.0E002
-3.11771E001 -3.11530E001 2.40945E-002
8.71949E-002 7.5E002 -3.57844E001
-3.57729E001 1.15029E-002 7.46033E-002
8.0E002 -4.07078E001 -4.07144E001
-6.59053E-003 5.65098E-002 8.5E002
-4.59470E001 -4.59782E001 -3.11241E-002
3.19762E-002 9.0E002 -5.15017E001
-5.15648E001 -6.31004E-002 0.00000E000
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Tolerance Analysis

• Sensitivity analysis of alignment
• Monte Carlo modeling

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Wavefront Sensing and Telescope Collimation

• Tests with OPTIC using a calcite block to make
  extrafocal images
• OPTIC design has 0.5 disk at 4 separation
• PS design could be as much as an 8 disk at 10
  separation, enough for 50-100 resolution elements
  over pupil.

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In/extra Focal Images for Pan-STARRS

r 1.6 deg, SS filter
Extra
Intra
Extra Intra
Nominal intra- and extra focal images, 4.4
diameter pupil
100?m secondary decenter
0.01 deg secondary tilt
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Atmospheric Dispersion

• In the broad Solar System filter, atmospheric
  dispersion dominates other aberration for zenith
  distances over 10 deg.

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PSF Area vs. Air Mass
dispersion
seeing
charge diffusion
trailing loss
pixel
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Design Pan-STARRS Post PDR 3, incorporating an ADC
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A traditional ADC contains many additional
air-glass surfaces and does not achieve
acceptable image quality over the wide Pan-STARRS
field. Therefore we did not seriously consider
ADCs before PDR.
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ADC
The design chosen has a rotating prism between
fixed lenses. This avoids the large rotary seal
and presents less of an engineering challenge and
schedule risk.

• Refractive indices match at 656 nm
• Zero deviation
• No added glass/air interfaces
• No large diameter rotating seals
• Relaxed tolerances on the flat surfaces

Maximum correction
No correction
Siloxane
Fused silica
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ADC prototype during filling procedure
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Design Pan-STARRS Final 2 ADC on maximum
dispersion
Note Box is 5"x5"
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At 75 zenith distance, the ADC fully corrects
atmospheric dispersion
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Telescope Studies

• Vertex RSI, Richardson TX
• Common alt-az
• Common equatorial
• EOST, Tucson AZ
• Common alt-az
• Independent alt-az
• Independent equatorial

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Haleakala
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Schematic of EOS Ice Dome as PS1 Dome
PS1EOS Ice Dome
MAGNUM
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Mauna Kea
CFHT
UKIRT
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Conceptual Configurations for Pan-STARRS-4 in the
UH 2.2 m telescope building