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Cosmogenic 10 Be exposure ages from moraines in the Wallowa Mountains, Oregon, identify two maximal late Pleistocene glaciations at 21.1 ؎ 0.4 ka and 17.0 ؎ 0.3 ka and a minor glacial event at 10.2 ؎ 0.6 ka. Our new high-resolution chronology, integrated with other well-dated glacial records from the western United States, demonstrates substantial(More)
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Polarization in the telescope can limit high accuracy polarization measurements by introducing cross talk among the input solar Stokes parameters. The larger the degree of telescope polarization the more difficult it is to remove through calibration. This calibration itself is often difficult as it is not practical to routinely place calibration optics over(More)
This trade study presents a summary of several COSMO Technical Notes in an effort to evaluate the relative performance of reflecting vs refracting coronagraphs. Both large aperture and very low instrumental scattered light are required to measure Gauss-level line-of-sight integrated magnetic fields with scientifically interesting spatial and temporal(More)
Cosmogenic 3 He and 10 Be ages measured on surface boulders from the moraine sequence deposited by the northern outlet glacier of the Yellowstone ice cap indicate that the outlet glacier reached its terminal position at 16.5 ؎ 0.4 3 He ka and 16.2 ؎ 0.3 10 Be ka, respectively. Concordance of these ages supports the scaled production rates used for 3 He(More)
Mk4 calibrated intensity data from 2004 through early 2006 have been analyzed in an effort to understand instrumental and sky brightness values and variations. Data are calibrated using an opal glass attenuator. Its transmission value has an uncertainty of 30%. Wavelength is set by the quantum efficiency of the line array detector, RG695 cut on filter, and(More)
have weighed the relative merits of refractive and reflective primary objectives for the COSMO large coronagraph and recommend that the COSMO large coronagraph be comprised of a refractive primary with a diameter of 1.5 meters. This decision is based on studies which are presented in several COSMO Technical Notes 1,2,3,4,5 which will only be briefly(More)
Measuring magnetic fields in the solar corona requires a large aperture telescope with exceptionally low levels of scattered light. For internally-occulted coronagraphs the main source is scattering from dust or microroughness on the primary lens or mirror. We show refracting primaries offer significantly lower levels for both sources. To observe magnetic(More)
official positions of the Society. citizenship, gender, religion, or political viewpoint. Opinions presented in this publication do not reflect presentation of diverse opinions and positions by scientists worldwide, regardless of their race, includes a reference to the article's full citation. GSA provides this and other forums for the the abstracts only of(More)
SPINOR is a new spectro-polarimeter that will serve as a facility instrument for the Dunn Solar Telescope at the National Solar Observatory. This instrument is capable of achromatic operation over a very broad range of wavelengths , from ∼400 up to 1600 nm, allowing for the simultaneous observation of several visible and infrared spectral regions with full(More)