Browsing by Author "Walker, Arthur B.C. II"

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Calibration of multilayer mirrors for the Multi‐Spectral Solar Telescope Array II
(1995-06-20) Kankelborg, Charles; Plummer, James E.; Martinez-Galarce, Dennis S.; O'Neal, Ray H.; DeForest, Craig; Walker, Arthur B.C. II; Barbee, Troy W. Jr.; Weed, J.W.; Hoover, Richard B.; Powell, Forbes R.
The Multi-Spectral Solar Telescope Array II (MSSTA II), a rocket-borne solar observatory, was successfully flown on November 3, 1994 obtaining solar images in multiple XUV and FUV bands with an array of compact multilayer telescopes. Extensive measurements have recently been carried out on some of the multilayer telescopes at the Stanford Synchrotron Radiation Laboratory. These measurements are the first high spectral resolution calibrations of newly introduced MSSTA II instruments and instruments with lambda0 less than 130 angstrom. Previous measurements and/or calculations of telescope throughputs have been confirmed with greater accuracy. Results are presented on Mo/Si multilayer bandpasses, and multilayer bandpass changes with time.
Design and performance of thin foil XUV filters for the Multi‐Spectral Solar Telescope Array II
(1995-06-20) Plummer, James E.; DeForest, Craig; Martinez-Galarce, Dennis S.; Kankelborg, Charles; Gore, David B.; O'Neal, Ray H.; Walker, Arthur B.C. II; Powell, Forbes R.; Hoover, Richard B.; Barbee, Troy W. Jr.; Weed, J.W.
The redesigned payload of the Multi-Spectral Solar Telescope Array (MSSTA), the MSSTA II, was successfully flown on November 3, 1994. The multilayer mirrors used in the normal incidence optical systems of the MSSTA II are efficient reflectors for soft x-ray/extreme ultraviolet (EUV) radiation at wavelengths that satisfy the Bragg condition, thus allowing a narrow band of the soft x-ray/EUV spectrum to be isolated. When applied to solar observations the temperature response of an optical system is quite sensitive to telescope bandpass because of the high density of lines in the coronal spectrum. We have designed a set of thin foil filters in conjunction with our multilayer optics to eliminate contaminant lines and specular reflectivity, thus enhancing the temperature diagnostic capabilities of our instruments. Extensive measurements have recently been carried out on the thin foil filters at the Stanford Synchrotron Radiation Laboratory. We describe here the design and performance of thin foil filters developed for the MSSTA II.
High‐resolution imaging with multilayer telescopes: resolution performance of the MSSTA II telescopes
(1999-09-29) Martinez-Galarce, Dennis S.; Walker, Arthur B.C. II; Gore, David B.; Kankelborg, Charles; Hoover, Richard B.; Barbee, Troy W. Jr.; Boerner, P.
The Multi-Spectral Solar Telescope Array (MSSTA) is a sounding rocket-borne observatory composed of a set of normal-incidence multilayer-coated telescopes that obtained selected bandpass spectroheliograms of the Solar atmosphere. These spectroheliograms were recorded on specially fabricated XUV and FUV 70mm Kodak film. Rocket launches of this instrument payload took place in 1991 and 1994 at the White Sands Missile Test Range in New Mexico, sponsored by the NASA sounding rocket experiment program. Immediately prior to the 1994 launch, visible light focusing test of each telescope were performed in-situ using a 1951 Standard Air Force High Resolution Test-target, to measure optical resolution performance. We determined that the MSSTA II telescopes performed at diffraction-limited resolutions down to 0.70 arc-second at visible wavelengths. Based on these measurements, we calculated an upper-bound to the focusing errors that incorporate the sum of all uncorrelated system resolution errors that affect resolution performance. Coupling these upper-bound estimates with the in-band diffraction limits, surface scattering errors and payload pointing jitter, we demonstrate that eleven of nineteen MSSTA II telescopes - having negligible figures of focus errors in comparison to the corresponding visible diffraction limits - performed at sub arc-second resolution at their operation FUV/EUV/XUV wavelengths during flight. We estimate the in-band performance down to 0.14 +/- 0.08 second of arc.
Multi‐Spectral Solar Telescope Array VIII: the second flight
(1995-06-20) Walker, Arthur B.C. II; Allen, Maxwell; DeForest, Craig; Kankelborg, Charles; Martinez-Galarce, Dennis S.; Plummer, James E.; Hoover, Richard B.; Barbee, Troy W. Jr.; Gore, David B.
The Multi Spectral Solar Telescope Array (MSSTA) is a rocket borne observatory that utilizes an array of multi-layer and interference film coated telescopes to observe the solar atmosphere from the chromosphere to the corona, over a broad spectral range (VUV - soft x rays). The MSSTA is continuously evolved to incorporate new instruments, and to improve its ability to investigate specific topics related to the structure and dynamics of the solar atmosphere. We describe chromospheric and coronal observations recorded during the second flight of the MSSTA on November 3, 1994 at 1915 UT.
Optical focusing and alignment of the Multi‐Spectral Solar Telescope Array II payload
(1995-06-20) Gore, David B.; Hadaway, James B.; Hoover, Richard B.; Walker, Arthur B.C. II; Kankelborg, Charles
The Multi-Spectral Solar Telescope Array (MSSTA) is a sounding rocket borne observatory designed to image the sun at many spectral lines in soft x-ray, EUV, and FUV wavelengths. Of the nineteen telescopes flown on November 3, 1994 the two Cassegrain telescopes and three of the six Ritchey-Cretien telescopes were focussed at NASA/Marshall Space Flight Center (MSFC) with a Zygo double-pass interferometer to determine the best positions of back focus. The remaining three Ritchey-Cretien and eleven Herschellian telescopes were focussed in situ at White Sands Missile Range by magnifying the telescopic image through a Gaertner traveling microscope and recording the position of best focus. From the data obtained at visible wavelengths, it is not unreasonable to expect that many of our telescopes did attain the sub-arc second resolution for which they were designed.
Performance of the multilayer‐coated mirrors for the MultiSpectral Solar Telescope Array
(1994-02-01) Allen, Maxwell; Willis, Thomas D.; Kankelborg, Charles; O'Neal, Ray H.; Martinez-Galarce, Dennis S.; DeForest, Craig; Jackson, Lisa R.; Plummer, James D.; Walker, Arthur B.C. II; Barbee, Troy W. Jr.; Weed, J.W.; Hoover, Richard B.
The Multi-Spectral Solar Telescope Array, a rocket-borne solar observatory, was successfully flown in May, 1991, obtaining solar images in eight XUV and FUV bands with 12 compact multilayer telescopes. We report on recent measurements of the performance of multilayer coated mirrors for the Multi Spectral Solar Telescope Array, carried out at the Stanford Synchrotron Radiation Laboratory.