UH/IfA commitments to ATST and its science

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UH/IfA commitments to ATST and its science
Principle NSF/ATST grant participants J.R. Kuhn,
R. Coulter, H. Lin, D. Mickey

• Some of the most exciting science in the next
  decade will come from coronal ATST observations
• SOLARC The worlds largest off-axis reflecting
  coronagraph is on Haleakala (built as partnership
  with AFOSR, NASA)
• Lessons learned for ATST

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Images arent enough
(from Chen et al., Low, Gibson)
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Our dark energy problem
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Why an IR (reflecting) off-axis coronagraph?

• Zeeman magnetic sensitivity
• Lower scattered sky background
• Lower scattered instrument optics background
• Lowered scattered dust background

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Scattering sources

• Atmosphere
• seeing
• aerosols
• atomic molecular scattering
• Telescope
• diffraction
• mirror roughness
• mirror dust

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Atmospheric backgrounds
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Optical backgrounds
Mirror roughness
Diffraction
4.0m
0.5m
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SOLARC

• Reflecting - broadband, IR
• Off-axis - unobscured, low scattering, relatively
  fast optical configuration

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SOLAR-C
Gregorian focus 8m f.l.
M2
M1 0.5m F/3.7
F/20, efl 8m, prim-sec 1.7m 0.5m, 1.5m fl
primary 55mm, secondary l/10 p-v figure diff.
Limited _at_ 1micron over 15fov 10.4 deg tilt angle
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(No Transcript)
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Measured secondary PSF
Over 5 orders of magnitude no mirror or other
spurious scatter terms detected
l 656 nm
Short exposure images nearly diffraction limited
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Prime focus occulter issues
Secondary
Prime focus, occulter
Final image
Lyot stop
Primary
(M2 illumination from limb)
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SOLARC photosphere observations achieve high
resolution
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Summary

• The SOLARC off-axis coronagraph on Haleakala is
  operational as test-bed
• Optical fabrication and alignment issues are
  quite comparable to a conventional telescope
• Post-focus instrumentation includes
• 1-5 micron imager
• Near and mid-IR spectrograph

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UH/IfA ATST Contributions

• SOLARC design concept and testbed
• Sky brightness monitor design and fabrication
• Haleakala site survey activities
• Infrared spectrograph design concepts (coronal
  and disk)
• Contributions toward global ATST EA/EIS studies