Solar Instrumentation II Posters
Presiding: L Strachan, Harvard-Smithsonian Center for Astrophysics; J Schmelz, University of Memphis
SP43A-01 1330h
The Calibration of the Solar-B X-ray Telescope (XRT)
The Solar-B X-ray telescope (XRT) is designed to have a wide temperature sensitivity in order to observe and analyze both the high (5-10 MK) and low temperature (1-5 MK) phenomena in the coronal plasma. It will be the telescope with the highest resolution ever flown for solar coronal studies. The telescope is designed for full Sun imaging over the wavelength range 6-60 Angstroms. The XRT is a grazing-incidence modified Wolter I X-ray telescope, of 35 cm inner diameter and 2.7 m focal length. The 2048 X 2048 back illuminated CCD has 13.5 æm pixels, corresponding to 1 arcsecond. The filter set used in the XRT, mounted at the telescope entrance and near the focal plane, will perform three functions: (1) to reduce the heat load inside the telescope, (2) to reduce the incoming visible light and (3) to provide spectral diagnostics to determine coronal plasma temperatures. This paper will present the results of the XRT calibration performed at the X-ray Calibration Facility, NASA-MSFC, Huntsville, Alabama in January 2005. We will discuss the methods and the most significant results of the XRT performance, namely: imaging properties, encircled energy, the point response function and the effective area in the 0.2-2 keV energy range.
SP43A-02 1330h
The Extreme Ultraviolet Imaging Spectrometer on Solar-B
The Extreme Ultraviolet Imaging Spectrometer (EIS) is currently under development for flight on the Japanese Solar-B satellite. EIS uses a multilayer-coated off-axis telescope mirror and a multilayer-coated toroidal grating spectrometer to produce stigmatic spectra of solar regions isolated by a 1024 arcsec high slit. The instrument produces monochromatic images either by rastering the solar image across a narrow entrance slit or by using a very wide slit. Half of each optic is coated to optimize reflectance at 19.5 nm, and the other half to optimize reflectance at 27.0 nm, with each wavelength range imaged onto a separate CCD detector. EIS can provide key dynamical and density diagnostic information. Combining EIS data with observations from the other instruments on Solar-B should provide a detailed picture of solar atmospheric processes from the visible surface into the corona. In this presentation, we provide details of the instrument's expected performance based on calibration of the individual flight optics and end-to-end testing at the Rutherford Appleton Laboratory in the UK.
SP43A-03 1330h
The Focal Plane Package for the Solar Optical Telescope on Solar-B
Solar-B is a space science mission of the Japanese Aerospace Exploration Agency (JAXA) and a NASA Solar Terrestrial Probes mission. It includes the 50-cm aperture Solar Optical Telescope (SOT), with its Focal Plane Package (FPP) designed for high resolution photospheric and chromospheric imaging and spectro-polarimetry. There are also two coronal instruments, the X-Ray Telescope and Extreme-ultraviolet Imaging Spectrometer. Solar-B will be launched into a Sun-synchronous polar orbit in August, 2006. The SOT is provided by JAXA and is being built by the National Astronomical Observatory of Japan (NAOJ) and Mitsubishi Electric Co. A team of Lockheed Martin, High Altitude Observatory (HAO), and NAOJ scientists and engineers have built the FPP instrument. This paper gives an overview of the science goals of the FPP as well as the instrument performance characteristics. The primary goal is to understand the coupling between the fine magnetic structures in the photosphere and dynamic processes and heating in the chromosphere and corona. The FPP consists of a narrow-band tunable birefringent filter imager, broad-band interference filter imager, and spectro-polarimeter (SP), essentially a space version of the HAO Advanced Stokes Polarimeter. The image is stabilized by a correlation tracker and active tilt mirror. The SP makes vector magnetic measurements from Stokes spectra of the Fe I lines 630.1 and 630.2 nm, with 0.16 arcsec pixels and field of view up to 164 x 328 arcsec. The broad-band system takes diffraction-limited images (0.05 arcsec pixels) in the Ca II H line, CN and G bandheads, and continuum bands. The narrow-band system makes filtergrams, magnetograms, Dopplergrams, and Stokes images in several photospheric lines, Mg b, Na D, and H-alpha, similar to the SOUP filter at La Palma. It has 0.08 arcsec pixels and field-of-view same as that of the SP. SOT and FPP have been calibrated in great detail and have observed the sun in two end-to-end tests at NAOJ. Sample results of these observations will be shown. Observing programs and coordination with the other instruments and observatories during the mission will be managed by SOT/FPP science planners, similar to those of SOHO and TRACE. The FPP project is supported by NASA (NAS8-01002).
SP43A-04 1330h
Calibration and Tesing of the Tunable Filter on Solar B
The tunable filter in the Focal Plane Package (FPP) on the Japanese Solar B satellite, scheduled for launch in August 2006, was designed, built, and tested at the Lockheed Martin Advanced Technology Center (LMATC). It is an eight element wide field calcite filter (an improved Lyot type) with a spectral resolution of about 100mÃ… and a tuning range of 11.87Ã… at 6302Ã…. Using 6 prefilters, it operates in bands covering the 5172Ã… Fe I, 5250Ã… Fe I, 5576Ã… Fe I, 5896Ã… Na I, 6302Ã… Fe I, and 6563Ã… H I lines. Here we describe the testing and calibrations used to determine the tuning parameters as functions of temperature and wavelength for the six bands. We also measure performance using sunlight and laser sources in a standalone mode and integrated into the FPP package. Images and derived magnetograms and Dopplergrams using a low resolution solar image have also been obtained while attached to the Solar B telescope and using a heliostat at the LMATC in Palo Alto. In the course of this work we have also refined the mathematical description for these types of filters, especially the error terms that arise from residual misalignments. In particular, we now believe we understand the intensity oscillations seen in this and earlier Lyot tunable filters.
SP43A-05 1330h
The Helioseismic and Magnetic Imager for the Solar Dynamics Observatory
The primary goal of the Helioseismic and Magnetic Imager (HMI) investigation is to study the origin of solar variability and to characterize and understand the Sun's interior and the various components of magnetic activity. The HMI investigation is based on measurements obtained with the HMI instrument as part of the Solar Dynamics Observatory (SDO) mission. HMI makes measurements of the motion of the solar photosphere to study solar oscillations and measurements of the polarization in a spectral line to study all three components of the photospheric magnetic field. Here we will give an overview of the HMI science goals, the HMI instrument and its expected performance, the science products produced and the ways in which the science community and public will be able to utilize HMI data.
http://hmi.stanford.edu
SP43A-06 1330h
Measured Pre-Flight Performance of the Extreme Ultraviolet Normal Incidence Spectrograph (EUNIS)
The Extreme Ultraviolet Normal-Incidence Spectrograph (EUNIS) is a sounding rocket experiment that will investigate the energetics of the solar corona and hotter transition region through high-resolution imaging spectroscopy with a rapid (2 s) cadence. EUNIS features independent optical systems to record spatially co-aligned spectra over the two bandpasses 170--205 Ã… and 300--370 Ã… simultaneously. All the components in the detection chain have been characterized, including multilayer telescope mirrors, lithographic slits, multilayer diffraction gratings, microchannel plate intensifiers, and active pixel sensors. The results demonstrate that EUNIS is the most sensitive solar EUV spectrograph in existence. Its first flight is scheduled for 2005 August.
SP43A-07 1330h
The New Solar Telescope at Big Bear Solar Observatory - A Progress Report
The New Solar Telescope (NST) is a new 1.6-meter, off-axis telescope for the Big Bear Solar Observatory (BBSO) in California. The NST is collaboration between BBSO, the Korean Astronomical Observatory (KAO) and Institute for Astronomy (IfA) at the University of Hawaii. BBSO is an ideal site for high-spatial resolution observations, since this mountain-lake site provides consistent seeing conditions with extended periods of excellent seeing from sunrise to sunset. These unique seeing characteristics make BBSO ideally suited for combined high-resolution campaigns and synoptic observations, which are essential for studies of solar activity and space weather. In this progress report, we present the latest information on the optical design, the optical support structure, the telescope control system and the requisite instrumentation for the telescope. Acknowledgements: This work has been supported by NSF under grants ATM-0236945, ATM-0342560, MRI-0320540, and Air Force DURIP F-49620-03-1-0271.
http://www.bbso.njit.edu
SP43A-08 1330h
First Light for the Near-Infrared Narrow-Band Tunable Birefringent Filter of the Big Bear Solar Observatory
A new near-infrared, narrow-band tunable birefringent filter has been developed by BBSO/NJIT. This filter, one of the first Lyot filters in the near-infrared, has a FWHM of about 2.5 ~Ã… at the design wavelength of 1.5648 Îœm and is used to observe the deepest levels of the photosphere. New techniques were employed in the design, including liquid crystal retarders to tune the center wavelength in range of ± 100 ~Ã…. After finishing the calibration and evaluation of the filter at the Evans Facility of the NSO at Sacramento Peak, high spatial resolution filtergrams and imaging spectroscopy observations were carried out at the Dunn Solar Telescope of NSO in December 2004 with the use of the high-order Adaptive Optics System. For some of these observations, the Lyot filter was combined with a Fabry-Perot Etalon to achieve a much higher spectral resolution. We discuss the calibration methods and present some preliminary observation results.
SP43A-09 1330h
Antenna Configurations for the FASR B Array
The proposed Frequency-Agile Solar Radiotelescope (FASR) is to produce high space, time, and frequency resolution full disk solar images. These will allow the reconstructions of the 3-D structure of the Sun's atmosphere from chromosphere to mid-corona. The high resolutions are required to carry out detailed diagnostics of fast-moving phenomena, such as flares and CMEs, as well as of quasi-static structures above active and quiet regions. The full disk images will capture all activity in the corona, even when there are many active regions at solar maximum. One of the tasks necessary to ensure optimal imaging for the array is to determine the best antenna configuration. The current poster presents work done towards this goal. We focus on the FASR-B array, which will cover the 200-3000 MHz range with 60 to 90 antennas of 6-m diameter. We have examined the imaging characteristics for a 3 arm, log-spiral configuration with radius of about 3 km. Multi-frequency observations are simulated for arrays varying in initial antenna spacing, number of antenna elements, and number of turns for each arm. The images reconstructed from the simulated snapshot observations are compared to the original model, convolved with the appropriate beam, to see which configuration yields the most faithful images. We discuss the implications of the findings for the planning of the FASR array configurations.
SP43A-10 1330h
Concept of a Wavelength Tunable Solar Polarimetry
Wavelength tunability of a typical solar polarimetry is limited to its design wavelength and very close to that. Any change in the wavelength will drastically reduce the efficiency of the polarization measurement. A new design for a polarization modulator has been studied and is found to be tunable for a large wavelength range. The design involves three zero-order polymer retarder and combinining them suitably. The basic principle of the design is similar to that of the well-known Pancharatnam technique for an achromatic waveplate design. A theoretical understanding of this tunable modulator design will be presented. The wavelength tunability of this design will be compared with other modulator preformances.