Author name code: marquette ADS astronomy entries on 2022-09-14 author:"Marquette, William H." ------------------------------------------------------------------------ Title: Performance of Major Flare Watches from the Max Millennium Program (2001 - 2010) Authors: Bloomfield, D. S.; Gallagher, P. T.; Marquette, W. H.; Milligan, R. O.; Canfield, R. C. Bibcode: 2016SoPh..291..411B Altcode: 2015arXiv151204518B; 2016SoPh..tmp....1B The physical processes that trigger solar flares are not well understood, and significant debate remains around processes governing particle acceleration, energy partition, and particle and energy transport. Observations at high resolution in energy, time, and space are required in multiple energy ranges over the whole course of many flares to build an understanding of these processes. Obtaining high-quality, co-temporal data from ground- and space- based instruments is crucial to achieving this goal and was the primary motivation for starting the Max Millennium program and Major Flare Watch (MFW) alerts, aimed at coordinating observations of all flares ≥ X1 GOES X-ray classification (including those partially occulted by the limb). We present a review of the performance of MFWs from 1 February 2001 to 31 May 2010, inclusive, which finds that (1) 220 MFWs were issued in 3407 days considered (6.5 % duty cycle), with these occurring in 32 uninterrupted periods that typically last 2 - 8 days; (2) 56% of flares ≥ X1 were caught, occurring in 19 % of MFW days; (3) MFW periods ended at suitable times, but substantial gain could have been achieved in percentage of flares caught if periods had started 24 h earlier; (4) MFWs successfully forecast X-class flares with a true skill statistic (TSS) verification metric score of 0.500, that is comparable to a categorical flare/no-flare interpretation of the NOAA Space Weather Prediction Centre probabilistic forecasts (TSS = 0.488). Title: The Big Bear Solar Observatory Ca II K-line index for solar cycle 23 Authors: Naqvi, M. F.; Marquette, W. H.; Tritschler, A.; Denker, C. Bibcode: 2010AN....331..696N Altcode: No abstract at ADS Title: Synoptic Observing at Big Bear Solar Observatory Authors: Denker, C.; Naqvi, M.; Deng, N.; Tritschler, A.; Marquette, W. H. Bibcode: 2007ASPC..368..515D Altcode: Synoptic solar observations in the chromospheric absorption lines Ca II K and Hα have a long tradition at Big Bear Solar Observatory (BBSO). The advent of the New Solar Telescope (NST) will shift the focus of BBSO's synoptic observing program toward high-resolution observations. We present an overview of the telescopes and instrumentation and show some of the most recent results. This includes Ca II K data to track solar irradiance variations, Hα full-disk data to monitor eruptive events, Dopplergrams from two-dimensional spectroscopy, as well as image restorations of diffraction-limited quality. Title: The New Solar Telescope at Big Bear Solar Observatory - A Progress Report Authors: Denker, C.; Cao, W.; Chae, J.; Coulter, R.; Kuhn, J. R.; Marquette, W. H.; Moon, Y.; Park, Y.; Ren, D.; Tritschler, A.; Varsik, J. R.; Wang, H.; Yang, G.; Shoumko, S.; Goode, P. R. Bibcode: 2005AGUSMSP43A..07D Altcode: 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. Title: The New Solar Telescope at Big Bear Solar Observatory Authors: Denker, C.; Marquette, W. H.; Varsik, J.; Wang, H.; Goode, P. R.; Moretto, G.; Kuhn, J.; Coulter, R. Bibcode: 2004AAS...204.6908D Altcode: 2004BAAS...36R.795D The New Solar Telescope (NST) at Big Bear Solar Observatory is the replacement of the current 65 cm vacuum telescope. We present the optical design of this novel off-axis telescope with a 1.6 m clear aperture. The NST has been designed to exploit the excellent seeing conditions at a lake-site observatory and provide data with a spatial resolution close the telescope's diffraction limit from the visible to the near-infrared (NIR) wavelength region. The post-focus instrumentation is located in the Coudé-room, a new optical laboratory below the observing floor, which also hosts a high-order adaptive optics system. The main instruments are two imaging spectro-polarimeters for visible and NIR observations and a real-time image reconstruction system for visible-light multi-color photometry. This unique combination of instruments will realize its full potential in the studies of active region evolution and space weather forecasts. Title: First results from the NSO/NJIT solar adaptive optics system Authors: Rimmele, Thomas R.; Richards, Kit; Hegwer, Stephen; Fletcher, Stephen; Gregory, Scott; Moretto, Gilberto; Didkovsky, Leonid V.; Denker, Carsten J.; Dolgushin, Alexander; Goode, Philip R.; Langlois, Maud; Marino, Jose; Marquette, William Bibcode: 2004SPIE.5171..179R Altcode: The National Solar Observatory and the New Jersey Institute of Technology have developed two 97 actuator solar adaptive optics (AO) systems based on a correlating Shack-Hartmann wavefront sensor approach. The first engineering run was successfully completed at the Dunn Solar Telescope (DST) at Sacramento Peak, New Mexico in December 2002. The first of two systems is now operational at Sacramento Peak. The second system will be deployed at the Big Bear Solar Observatory by the end of 2003. The correlating Shack-Hartmann wavefront sensor is able to measure wavefront aberrations for low-contrast, extended and time-varying objects, such as solar granulation. The 97-actuator solar AO system operates at a loop update rate of 2.5 kHz and achieves a closed loop bandwidth (0dB crossover error rejection) of about 130 Hz. The AO system is capable of correcting atmospheric seeing at visible wavelengths during median seeing conditions at both the NSO/Sacramento Peak site and the Big Bear Solar Observatory. We present an overview of the system design. The servo loop was successfully closed and first AO corrected images were recorded. We present first results from the new, high order AO system. Title: Long-Term Seeing Characteristics at Big Bear Solar Observatory Authors: Denker, C.; Espinosa, O. D.; Nenow, J.; Marquette, W. H. Bibcode: 2003SPD....34.2018D Altcode: 2003BAAS...35R.847D We present observations of long-term seeing characteristics from June 1997 to September 2002 obtained with Seykora-type scintillometers at Big Bear Solar Observatory (BBSO). BBSO is an ideal site for ground-based campaign-style observations. Since BBSO is situated on a small island in a 2,000 m high mountain lake in the cloudless mountains of Souther California, it benefits from excellent seeing conditions all day long. The atmospheric turbulence that degrades images originates primarily from two layers near the ground and at the level of the jet stream. BBSO's dome is located at the end of a 300 m long causeway jutting into the lake. Since the lake, with its cool waters, provides a natural inversion, and the dome has three kilometers of open water to its west, the boundary layer seeing is effectively suppressed. In addition, the east-west orientation of the Big Bear Valley provides a natural channel for the prevailing winds from the west resulting in a nearly laminar flow at the observatory site. We present a comparison of scintillometer data with climate data and analyze a one year long sub-set for local seeing variations near the lake shore and at the observatory island.

We would like to thank Jacques Beckers and the National Solar Observatory for providing the scintillometer data. This work was supported by NSF under grant ATM 00-86999, ATM 00-76602, and ATM 02-36945 and by NASA under grant NAG 5-9682. Title: Hα Full Disk Observations of Chromospheric Differential Rotation Authors: Smith, G. A.; Varsik, J.; Nenow, J.; Marquette, W. H.; Wang, H.; Denker, C. Bibcode: 2003SPD....34.0708S Altcode: 2003BAAS...35..821S We studied the solar chromospheric rotation profile using full-disk Hα images of the Sun obtained at the Big Bear Solar Observatory (BBSO). The method is based on Local Correlation Tracking (LCT). As a unique feature the entire full-disk image is used, i. e., quiet sun as well as solar active regions, whereas most other methods rely on images of distinct individual features such as filaments, plages, and sunspots. Six months of Hα full-disk data sets from June to December 2001, which consists of 600 to 800 daily images at 30 s to 60 s cadence, have been processed and analyzed. The images were checked for a number of problems, including overexposure, underexposure, and skewed images. All images were normalized by having the solar disk recentered, the dark frame subtracted, and the limb darkening function calculated and subtracted from the image. The images are locally cross-correlated with each other to find the displacements between them. The angular velocities are projected onto the central meridian and a differential rotation profile is fitted to the data (either as Legendre polynomials or as polynomials in sin 2nθ , quad n=0,1, 2, ..., where θ is the heliographic longitude). The currently used settings in the processing of the six months data were optimized for both accuracy and speed. A number of different parameters were experimented with, such as various grid sizes, grid spacing, sampling window sizes, weighing functions and also different implementations of cross-correlation algorithms, to find the best combination.

This work was supported by NSF under grant ATM 00-86999, ATM 00-76602, and ATM 02-36945 and by NASA under grant NAG 5-9682. Title: Solar adaptive optics: a progress report Authors: Rimmele, Thomas R.; Richards, Kit; Hegwer, Steven L.; Ren, Deqing; Fletcher, S.; Gregory, Scott; Didkovsky, Leonid V.; Denker, Carsten J.; Marquette, William; Marino, J.; Goode, Philip R. Bibcode: 2003SPIE.4839..635R Altcode: We present a progress report of the solar adaptive optics (AO) development program at the National Solar Observatory (NSO) and the Big Bear Solar Observatory (BBSO). Examples of diffraction-limited observations obtained with the NSO low-order solar adaptive optics system at the Dunn Solar Telescope (DST) are presented. The design of the high order adaptive optics systems that will be deployed at the DST and the BBSO is discussed. The high order systems will provide diffraction-limited observations of the Sun in median seeing conditions at both sites. Title: High-order adaptive optical system for Big Bear Solar Observatory Authors: Didkovsky, Leonid V.; Dolgushyn, Alexander; Marquette, William; Nenow, Jeff; Varsik, John; Goode, Philip R.; Hegwer, Steven L.; Ren, Deqing; Fletcher, Steve; Richards, Kit; Rimmele, Thomas; Denker, Carsten J.; Wang, Haimin Bibcode: 2003SPIE.4853..630D Altcode: We present a high-order adaptive optical system for the 26-inch vacuum solar telescope of Big Bear Solar Observatory. A small elliptical tip/tilt mirror is installed at the end of the existing coude optical path on the fast two-axis tip/tilt platform with its resonant frequency around 3.3 kHz. A 77 mm diameter deformable mirror with 76 subapertures as well as wave-front sensors (correlation tracker and Shack-Hartman) and scientific channels for visible and IR polarimetry are installed on an optical table. The correlation tracker sensor can detect differences at 2 kHz between a 32×32 reference frame and real time frames. The WFS channel detects 2.5 kHz (in binned mode) high-order wave-front atmosphere aberrations to improve solar images for two imaging magnetographs based on Fabry-Perot etalons in telecentric configurations. The imaging magnetograph channels may work simultaneously in a visible and IR spectral windows with FOVs of about 180×180 arc sec, spatial resolution of about 0.2 arc sec/pixel and SNR of about 400 and 600 accordingly for 0.25 sec integration time. Title: Seeing Characteristic at a Lake-Site Observatory Authors: Denker, C.; Didkovsky, L.; Marquette, W. H.; Goode, P. R.; Venkateswaran, K.; Rimmele, T. R. Bibcode: 2003ASPC..286...23D Altcode: 2003ctmf.conf...23D No abstract at ADS Title: Control and Acquisition Software for the Visible-Light Fabry-Pérot Interferometer at the Big Bear Solar Observatory Authors: Shumko, Sergiy; Denker, Carsten J.; Varsik, John; Didkovsky, Leonid V.; Marquette, William; Goode, Philip R.; Wang, Haimin Bibcode: 2002SPIE.4848..483S Altcode: We describe our progress in the development of a software package to control a Fabry-Pérot interferometer (FPI) at the Big Bear Solar Observatory (BBSO). The FPI is a key part of our new Visible-Light Imaging Magnetograph (VIM). We describe the software libraries and methods that we use to develop the software. We also present specifications and characteristics of this new instrument. Title: The new global high-resolution Hα network: preliminary results on the chromospheric differential rotation Authors: Steinegger, M.; Denker, C.; Goode, P. R.; Marquette, W. H.; Varsik, J.; Wang, H.; Otruba, W.; Freislich, H.; Hanslmeier, A.; Luo, G.; Chen, D.; Zhang, Q. Bibcode: 2001ESASP.464..315S Altcode: 2001soho...10..315S A new global network for high-resolution Hα full-disk observations of the sun has been established at the Big Bear Solar Observatory (U.S.A.), the Kanzelhöhe Solar Observatory (Austria), and the Yunnan Astronomical Observatory (China). Each of the three stations have a 2K×2K pixel CCD detector available to monitor the sun with a spatial resolution of 1 arcsec per pixel and a cadence of at least 1 image per minute. Having high-cadence data from three observing stations available enables us to accurately track solar rotation rates and meridional motions by local correlation (LCT) and feature tracking techniques. This includes, e.g., tracking over several days the motions around active regions. After an overview of the new Hα network and its scientific objectives, we present and discuss the first preliminary results of the determination of the chromospheric differential rotation by LCT from a high-cadence time-series of Hα full-disk images. The obtained equatorial rotation rate of 13.3044 deg/day (2.6876 μrad/s) agrees well with the values obtained by other authors. Finally, we briefly outline our future plans for the continuation of this work. Title: The Big Bear Solar Observatory's Digital Vector Magnetograph Authors: Spirock, T.; Denker, C.; Chen, H.; Chae, J.; Qiu, J.; Varsik, J.; Wang, H.; Goode, P. R.; Marquette, W. Bibcode: 2001ASPC..236...65S Altcode: 2001aspt.conf...65S No abstract at ADS Title: Synoptic Observations of the Sun from Big Bear Solar Observatory (CD-ROM Directory: contribs/goode) Authors: Goode, P. R.; Denker, C.; Marquette, W. H.; Wang, H. Bibcode: 2001ASPC..223..656G Altcode: 2001csss...11..656G No abstract at ADS Title: Dynamics of Quiet Sun Magnetic Fields Authors: Denker, C.; Spirock, T.; Varsik, J. R.; Chae, J.; Marquette, W. H.; Wang, H.; Goode, P. R. Bibcode: 2001ASPC..236..463D Altcode: 2001aspt.conf..463D No abstract at ADS Title: Multi-Wavelength Observations of Solar Fine-Structure with High Spatial Resolution (CD-ROM Directory: contribs/denker) Authors: Denker, C.; Spirock, T. J.; Jefferies, S. M.; Chen, H.; Marquette, W. H.; Wang, H.; Goode, P. R. Bibcode: 2001ASPC..223..607D Altcode: 2001csss...11..607D No abstract at ADS Title: Measuring Seeing from Solar Scintillometry and the Spectral Ratio Technique Authors: Goode, P. R.; Wang, H.; Marquette, W. H.; Denker, C. Bibcode: 2000SoPh..195..421G Altcode: In principle, the optical transfer function can be described by a single parameter, the Fried parameter r0, which reveals the net effect of the turbulence along the line of sight. We present measurements of the Fried parameter obtained from the spectral ratio technique and compare them to data from solar scintillometry and from angle-of-arrival fluctuations. The measurements were performed at the Big Bear Solar Observatory (BBSO) in 1997 and 1998 - before and after a series of steps were taken to reduce dome seeing. The results show that the dome seeing was considerably reduced and now approaches the seeing conditions measured outside the dome. The Fried parameter as measured by the spectral ratio technique now frequently exceeds r0=10 cm at our lake site observatory. Accounting for the remaining dome and window seeing, the scintillometer and the angle-of-arrival data imply the potential for an r0>20 cm for BBSO during days of good seeing. Title: Hα Linear Polarization Observations of Solar Flares: The Search for Proton Beams Authors: Johns-Krull, C. M.; Fisher, G. H.; Varsik, J.; Marquette, W. Bibcode: 2000SPD....31.0254J Altcode: 2000BAAS...32..820J The role of ~ 100 keV proton beams in flare energy transport is currently unknown. Claims in the literature range from an energetically negligible role for such protons during flares to claims that 100 keV proton beams carry the majority of the energy released in the corona to the photosphere during a solar flare. Much of the uncertainty concerning protons is due to the fact that 100 keV protons produce very few distinguishable radiative emissions. One such distinguishing emission is the production of linear polarization in the core of the Hα emission line during the impulsive phase of a solar flare. This linear polarization is produced as accelerated, directed, protons collide with ambient hydrogen atoms in the solar chromosphere. The geometry of the situation is such that the linear polarization should be strongest at the limb of the Sun and vanish at disk center, while the orientation of the polarization should always be along the line between the flare location and disk center. The expected signal is 5 -- 10% linear polarization at the limb. We have modified the Big Bear Solar Observatory (BBSO) video magnetograph (VMG) to operate in the core of the Hα line. Here, we present observations of a handful of solar flares using this system. We show that our sensitivity level is ~ 1%, and we discuss in detail observations of a long duration GOES class M2 flare observed at the West limb on 5 August 1999. CMJ-K would like to acknowledge partial funding support of this work by CalSpace. Title: The New Global High-Resolution Hα Network: First Observations and First Results Authors: Steinegger, M.; Denker, C.; Goode, P. R.; Marquette, W. H.; Varsik, J.; Wang, H.; Otruba, W.; Freislich, H.; Hanslmeier, A.; Luo, G.; Chen, D.; Zhang, Q. Bibcode: 2000ESASP.463..617S Altcode: 2000sctc.proc..617S No abstract at ADS Title: Large-Scale Structures of Solar Flares Authors: Denker, C.; Marquette, W.; Wang, H.; Goode, P. R.; Johannesson, A. Bibcode: 1999AAS...194.2207D Altcode: 1999BAAS...31..860D Since December 1997, the Big Bear Solar Observatory (BBSO) has provided daily, contrast enhanced, Hα full disk images of unsurpassed quality, temporal resolution of about 30 s, and spatial resolution of about 2 arcsec which allow us to study the evolution of small-scale structures and low-contrast features. This data set has the right qualities to allow us to study large-scale phenomena associated with major solar flares such as Moreton waves, transient brightening of the Hα network, filament eruptions and disappearances. In 1998, 31 flares of magnitude M3.0 or larger were observed by the Geosynchronous Operational Environmental Satellites (GOES). Eight of them occurred during the typical observing hours at BBSO and seven were actually covered by Hα full disk observations presented here. We provide a detailed description of various chromospheric disturbances initiated by the flares, the influence of magnetic fields on their appearance, and their association with coronal mass ejections. This work was supported by ONR under grant N00014-97-1-1037, by NSF under grant ATM 97-14796, and by NASA under grant NAG 5-4919 and NAG 5-7350. Title: Solar Asphericities from BBSO Synoptic Data and MDI Splittings Authors: Goode, P. R.; Dziembowski, W. A.; Marquette, W. Bibcode: 1999AAS...194.4205G Altcode: 1999BAAS...31..882G Beneath the photosphere, on average the Sun is almost a perfect sphere. Historically, the main photospheric asymmetry studied has been the magnetic activity cycle as reflected in the Maunder butterfly diagram. In recent years, more subtle signatures of asymmetries varying with the solar cycle have been found. We have used temporal averages of BBSO synoptic maps from the activity minimum which has just ended to extract the low degree Legendre dependence of the data. We present preliminary comparisons of the degree of correlation between these Legendre coefficients varying through the solar cycle with the temporally corresponding low degree Legendre coefficents from MDI splitting data to enable us to garner another perspective, the role of the magnetic field in the Sun's cycle dependent asphericity. Title: Acoustic Imaging in Helioseismology Authors: Chou, Dean-Yi; Chang, Hsiang-Kuang; Sun, Ming-Tsung; LaBonte, Barry; Chen, Huei-Ru; Yeh, Sheng-Jen; TON Team; Tang, Heng-Tai; Shiu, Wei-Cheng; Chen, Yi-Liang; Jimenez, Antonio; Rabello-Soares, Maria Cristina; Ai, Guoxiang; Wang, Gwo-Ping; Goode, Philip; Marquette, William; Ehgamberdiev, Shuhrat; Khalikov, Shukur Bibcode: 1999ApJ...514..979C Altcode: The time-variant acoustic signal at a point in the solar interior can be constructed from observations at the surface, based on the knowledge of how acoustic waves travel in the Sun: the time-distance relation of the p-modes. The basic principle and properties of this imaging technique are discussed in detail. The helioseismic data used in this study were taken with the Taiwan Oscillation Network (TON). The time series of observed acoustic signals on the solar surface is treated as a phased array. The time-distance relation provides the phase information among the phased array elements. The signal at any location at any time can be reconstructed by summing the observed signal at array elements in phase and with a proper normalization. The time series of the constructed acoustic signal contains information on frequency, phase, and intensity. We use the constructed intensity to obtain three-dimensional acoustic absorption images. The features in the absorption images correlate with the magnetic field in the active region. The vertical extension of absorption features in the active region is smaller in images constructed with shorter wavelengths. This indicates that the vertical resolution of the three-dimensional images depends on the range of modes used in constructing the signal. The actual depths of the absorption features in the active region may be smaller than those shown in the three-dimensional images. Title: Synoptic Hα Full-Disk Observations of the Sun from Big Bear Solar Observatory - I. Instrumentation, Image Processing, Data Products, and First Results Authors: Denker, C.; Johannesson, A.; Marquette, W.; Goode, P. R.; Wang, H.; Zirin, H. Bibcode: 1999SoPh..184...87D Altcode: The Big Bear Solar Observatory (BBSO) has a long tradition of synoptic full-disk observations. Synoptic observations of contrast enhanced full-disk images in the Ca ii K-line have been used with great success to reproduce the H i Lα irradiance variability observed with the Upper Atmosphere Research Satellite (UARS). Recent improvements in data calibration procedures and image- processing techniques enable us now to provide contrast enhanced Hα full-disk images with a spatial resolution of approximately 2'' and a temporal resolution of up to 3 frames min−1. Title: New Digital Magnetograph At Big Bear Solar Observatory Authors: Wang, H.; Denker, C.; Spirock, T.; Goode, P. R.; Yang, S.; Marquette, W.; Varsik, J.; Fear, R. J.; Nenow, J.; Dingley, D. D. Bibcode: 1998SoPh..183....1W Altcode: A new digital magnetograph system has been installed and tested at Big Bear Solar Observatory. The system uses part of BBSO's existing videomagnetograph (VMG) system: a quarter wave plate, a ferro-electric liquid crystal to switch polarizations, and a 0.25 Å bandpass Zeiss filter tuned at Ca i 6103 Å. A new 256×256 pixels, 12-bit Dalsa camera is used as the detector and as the driver to switch the liquid crystal. The data rate of the camera is 90 frames s−1. The camera is interfaced to a Pentium-166 PC with a μTech imaging board for data acquisition and analysis. The computer has 128 MByte of RAM, and up to 700 live images can be stored in memory for quick post-exposure image processing (image selection and alignment). We have significantly improved the sensitivity and spatial resolution over the old BBSO VMG system. In particular: (1) New digital image data are in 12 bits while the video signal is digitized as 8 bits. Polarizations weaker than 1% can not be detected by a single pair subtraction in the video system. The digital system can detect a polarization signal of about 0.3% by a single pair subtraction. (2) Data rate of the digital system is 90 frames s−1, that of the video system is 30 frames s−1. So the time difference between two polarizations is reduced in the new system. Under good seeing conditions, the data rate of 90 frames s−1 ensures that most of the wavefront distortions are `frozen' and fairly closely the same for the left and right circular polarized image pairs. (3) Magnetograms are constructed after image selection and alignment. We discuss the characteristics of this new system. We present the results of our first tests to reconstruct magnetograms with speckle interferometric techniques. We also present some preliminary results on the comparison of facular/micropore contrasts and magnetic field structure. The experiment with this small detector lays ground for a larger format digital magnetograph system at BBSO, as well as a future Fabry-Pérot system, which will be able to scan across the spectral line. Title: Magnetic Sources of the Solar Irradiance Cycle Authors: Lean, J. L.; Cook, J.; Marquette, W.; Johannesson, A. Bibcode: 1998ApJ...492..390L Altcode: Using recently processed Ca K filtergrams, recorded with a 1 Å filter at the Big Bear Solar Observatory (BBSO), we quantitatively assess the component of solar irradiance variability attributable to bright magnetic features on the Sun's disk. The Ca K filtergrams, ``flattened'' by removing instrumental effects and center-to-limb variations, provide information about bright sources of irradiance variability associated with magnetic activity in both active regions and dispersed active region remnants broadly distributed in the supergranule network (termed collectively ``faculae''). Procedures are developed to construct both total and UV spectral solar irradiance variations explicitly from the processed Ca K filtergrams, independently of direct irradiance observations. The disk-integrated bolometric and UV facular brightness signals determined from the filtergrams between late 1991 and mid-1995 are compared with concurrent solar irradiance measurements made by high-precision solar radiometers on the Upper Atmosphere Research Satellite (UARS). The comparisons suggest that active-region and active-network changes can account for the measured variations. This good agreement during a period covering most of the decline in solar activity from the cycle 22 maximum to the impending solar minimum directly implicates magnetic features as the sources of the 11 yr irradiance cycle, apparently obviating the need for an additional component other than spots or faculae. Title: A 10-Year Set of CA I K-Line Filtergrams Authors: Johannesson, Anders; Marquette, William H.; Zirin, Harold Bibcode: 1998sers.conf..265J Altcode: No abstract at ADS Title: A 10-Year Set of CA II K-Line Filtergrams Authors: Johannesson, Anders; Marquette, William H.; Zirin, Harold Bibcode: 1998SoPh..177..265J Altcode: We have processed a 10-year set of BBSO Caii K-line filtergrams covering most of solar cycle 22. The excess K-line emission is integrated to form linear and square-root activity indices that are fitted to UV data from UARS and SME. Good fits are found both for the Mgii core-wing ratio (linear) and total Lα irradiance (square root) and the indices are thus good proxies for UV data. The SME Lα irradiance is systematically lower by 20% than predicted from our corresponding K-line indices. The 10.7 cm radio data confirms that SME underestimated the flux. The network is partly responsible for the solar cycle variation of the indices and is relatively more important in Lα than in Mgii and Caii K. This is due to the saturation of Lα equivalent width. We also report on substantial improvements to the equipment and reduction software. The system is now based on a digital CCD camera which promises more accurate measurements in the upcoming solar cycle 23. Title: Comparison of Polar and Equatorial Magnetic Fields Near Sunspot Minimum Authors: Zhang, L. D.; Zirin, H.; Marquette, W. H. Bibcode: 1997SoPh..175...59Z Altcode: We investigate the polar magnetic fields near sunspot minimum using high-resolution videomagnetograph data from Big Bear Solar Observatory. To avoid the problem of center-to-limb variation of the projected longitudinal field, we compare polar with equatorial field strengths for the same limb distance. Polar fields are stronger than the quiet equatorial field, but no greater than equatorial limb data containing unipolar regions. The difference is entirely in the stronger field elements. The polar background fields are of mixed polarity but show a net weak field opposite in sign to that of the stronger polar elements. We believe this to be the first evidence of widespread background field. No dependence of the measured signal on the B-angle was found, so the high-latitude fields do not change strength near the pole. Further, there was no significant change in the polar fields in the 15-month period studied. We tried to derive a high-latitude rotation rate; our data show motion of high-latitude magnetic elements, but the diurnal trajectory is not much bigger than random motions and field changes, so the result is inconclusive. We suggest that the polar fields represent the accumulation of sunspot remnants, the elements of which last for years in the absence of other fields. Title: Comparison of Two Fitting Methods for Ring Diagram Analysis of Very High l Solar Oscillations Authors: Patrón, J.; González Hernández, I.; Chou, Dean-Yi; Sun, M. -T.; Mu, T. -M.; Loudagh, S.; Bala, B.; Chou, Y. -P.; Lin, C. -H.; Huang, I. -J.; Jiménez, A.; Rabello-Soares, M. C.; Ai, G.; Wang, G. -P.; Zirin, H.; Marquette, W.; Nenow, J.; Ehgamberdiev, S.; Khalikov, S.; TON Team Bibcode: 1997ApJ...485..869P Altcode: A new method of fitting tridimensional power spectra of solar oscillations is described and compared with a previous one whose use has been more common. The new method fits the parameters of the Lorentzian profiles in a bidimensional k - ω diagram constructed from an azimuthal average of the tridimensional one. The horizontal velocities are then determined keeping these parameters fixed, greatly reducing the computation time. Both methods are compared for two radial orders (n = 3, 4) of a tridimensional power spectrum obtained for a region of about 15° square around solar disk center. The images used in this work correspond to a 3 day set of 1080 × 1080 pixel intensity images obtained at the Observatorio del Teide on 1994 November 8-10 with the Taiwanese Oscillation Network (TON) instrument. The results of the fitted velocities agree within the estimated errors for the two methods. The reduction of the computing time obtained with the new method makes it convenient for the ring diagram analysis. Title: Modeling solar extreme ultraviolet irradiance variability using emission measure distributions Authors: Warren, H. P.; Mariska, J. T.; Lean, J.; Marquette, W.; Johannesson, A. Bibcode: 1996GeoRL..23.2207W Altcode: We introduce a new model of solar irradiance variability at extreme ultraviolet (EUV) wavelengths. The model combines a spectral emission line database, solar emission measure distributions, and estimates from ground-based solar images of the fraction of the Sun covered by the various types of activity to synthesize the irradiance. Using Call K-line images, the model can be used to estimate the irradiance from EUV line emission formed in the upper chromosphere and lower transition region. Comparisons of this new model with existing empirical models reveal both similarities and disagreements in the absolute magnitude, the amplitude of the rotational modulation, and the intermediate-term solar cycle variability of the predicted fluxes. Title: The Global Oscillation Network Group (GONG) Project Authors: Harvey, J. W.; Hill, F.; Hubbard, R. P.; Kennedy, J. R.; Leibacher, J. W.; Pintar, J. A.; Gilman, P. A.; Noyes, R. W.; Title, A. M.; Toomre, J.; Ulrich, R. K.; Bhatnagar, A.; Kennewell, J. A.; Marquette, W.; Patron, J.; Saa, O.; Yasukawa, E. Bibcode: 1996Sci...272.1284H Altcode: Helioseismology requires nearly continuous observations of the oscillations of the solar surface for long periods of time in order to obtain precise measurements of the sun's normal modes of oscillation. The GONG project acquires velocity images from a network of six identical instruments distributed around the world. The GONG network began full operation in October 1995. It has achieved a duty cycle of 89 percent and reduced the magnitude of spectral artifacts by a factor of 280 in power, compared with single-site observations. The instrumental noise is less than the observed solar background. Title: Facular Origin of the Sun's 11-year Total Radiation Cycle Authors: Lean, J.; Cook, J.; Marquette, W.; Johannesson, A.; Willson, R. Bibcode: 1996AAS...188.7901L Altcode: 1996BAAS...28Q.955L While the amplitude and temporal structure of the 11-year cycle in the Sun's total radiation is relatively well established from spacebased radiometry, the origins of the variations are not. Rotational modulation on shorter time scales is attributable to the changing presence on the Sun's Earth-facing disk of dark sunspots and bright faculae, both of which occur frequently during times of high solar activity but may be absent for days during solar minimum conditions. However, calculations of the energy changes in sunspots and active region faculae over the longer time scale of the 11-year cycle underestimate the observed solar cycle irradiance modulation by about a factor of two. This apparent lack of facular brightness has lead to speculation of a missing irradiance brightness component, and the possibility that a non facular -- perhaps global -- mechanism may be responsible for the observed total radiation energy changes. Recent analysis of Ca K filtergrams, recorded with a 1 Angstrom Daystar filter at the BBSO, suggest a methodology with which to quantitatively assess the contribution of facular brightness to total solar irradiance variations. Following removal of instrumental effects and limb variations from the Ca K images, the resultant "flattened" spectroheliograms provide a surrogate for facular brightness in both active regions and in the surrounding chromospheric network. Evolution of the globally integrated signal from enhanced Ca K emission on the full solar disk is compared with concurrent total solar irradiance measurements made by the ACRIM II radiometer on the Upper Atmosphere Research Stellite from 1992 to 1994. This period covers most of the decline in solar activity from the cycle 22 maximum to the impending solar minimum, and suggest that facular changes can account for essentially all the measured variations. Title: The Global Oscillation Network Group Project Authors: Leibacher, J. W.; Harvey, J. W.; Hill, F.; Hubbard, R.; Kennedy, J. R.; Pintar, J. A.; Bhatnagar, A.; Kennewell, J. A.; Marquette, W.; Patron, J.; Saa, O.; Yasukawa, E.; GONG Project Team Bibcode: 1996AAS...188.5301L Altcode: 1996BAAS...28..903L The NSF-sponsored Global Oscillation Network Group (GONG) project has developed and is operating a network of six velocity imaging instruments around the world, and a data analysis system that can keep up with the massive data flow, in support of a vigorous community that shares in all aspects of this program to explore the structure and dynamics of the solar interior. Data from the first three stations were obtained starting in March 1995, and the full six-station network became operational in early October 1995. The system noise is below the solar background of incoherent surface motions, and the overall data processing pipeline is maintaining cadence with the data flood. The scientific objectives, design and performance of the network, instrumentation, and data processing, and plans for the future will be presented. The National Optical Astronomy Observatories are operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation. Title: Reproduction of the Lyman \alpha Irradiance Variability from Analysis of Full-Disk Images in the CaII K-Line Authors: Johannesson, A.; Marquette, W.; Zirin, H. Bibcode: 1995SoPh..161..201J Altcode: We have compared three years of daily CaII K-line images from the Big Bear Solar Observatory (BBSO) with HI Lymanα irradiance data from the Upper Atmosphere Research Satellite (UARS). The daily full-disk CaII K-line images are reduced to a new index of integrated excess emission, which reproduces both the 27 day rotational modulation and the solar cycle decrease in Lyα irradiance. Our analysis shows that while plages reproduce the 27-day variation quite well, the total K-line emission excess above the quiet background is needed to reproduce the secular solar cycle trend in the Lyα irradiance. The resulting K-line index exhibits a high degree of correlation (0.9) with the time series of measured Lyα flux. Title: Taiwan Oscillation Network Authors: Chou, Dean-Yi; Sun, Ming-Tsung; Huang, Teng-Yi; Lai, Shih-Ping; Chi, Pi-Jen; Ou, Knight-Tien; Wang, Chang-Chi; Lu, Jui-Yang; Chu, An-Li; Niu, Chi-Seng; Mu, Tao-Mo; Chen, Kuan-Rong; Chou, Yung-Ping; Jimenez, Antonio; Rabello-Soares, Maria Cristina; Chao, Horance; Ai, Guoxiang; Wang, Gwo-Ping; Zirin, Harold; Marquette, William; Nenow, Jeff Bibcode: 1995SoPh..160..237C Altcode: The Taiwan Oscillation Network (TON) is a ground-based network to measure solar intensity oscillations to study the internal structure of the Sun. K-line full-disk images of 1000 pixels diameter are taken at a rate of one image per minute. Such data would provide information onp-modes withl as high as 1000. The TON will consist of six identical telescope systems at proper longitudes around the world. Three telescope systems have been installed at Teide Observatory (Tenerife), Huairou Solar Observing Station (near Beijing), and Big Bear Solar Observatory (California). The telescopes at these three sites have been taking data simultaneously since October of 1994. Anl - v diagram derived from 512 images is included to show the quality of the data. Title: A ground-based CaII K-line index as a proxy for the UARS Lyman α irradiance Authors: Johanesson, A.; Marquette, W.; Zirin, H. Bibcode: 1995SPD....26..511J Altcode: 1995BAAS...27..959J No abstract at ADS Title: Calcium Plage Observations at Big Bear Solar Observatory Authors: Marquette, W. Bibcode: 1992sers.conf..154M Altcode: No abstract at ADS Title: The Solar Cycle Pattern in the Direction of the Magnetic Field along the Long Axes of Polar Filaments Authors: Martin, Sara F.; Marquette, William H.; Bilimoria, Rajash Bibcode: 1992ASPC...27...53M Altcode: 1992socy.work...53M No abstract at ADS Title: The Evolution and Orientation of Early SOLAR-CYCLE-22 Active Regions Authors: Cannon, Anne T.; Marquette, William H. Bibcode: 1991SoPh..131...69C Altcode: The evolution of six major active regions which appeared during the first phase of the present solar cycle (cycle 22) has been studied. It was found that the northern hemisphere regions exhibited a broad range of evolutionary behavior in which the commonly accepted `normal pattern' (whereby the follower flux moves preferentially polewards ahead of the leader flux) is represented only at one end of the range. At the other end of the range, the leader flux is displaced polewards of the follower flux. In the latter cases equatorward extensions of the polar coronal hole are noted. Title: Modelling solar irradiances using ground-based measurements Authors: Pap, J. M.; Marquette, W. H.; Donnelly, R. F. Bibcode: 1991AdSpR..11e.271P Altcode: 1991AdSpR..11..271P The preliminary results of the photometry of Ca-K plage remnants show that during the fall of 1986 the remnants gave a significant contribution to the irradiance variations. The contribution of the plage remnants to the combined plage and remnant index was on average about 13 % and it changed with time. Title: BEARALERTS: A successful flare prediction system Authors: Zirin, Harold; Marquette, William Bibcode: 1991SoPh..131..149Z Altcode: We describe our BEARALERT program of predicting solar flares or rapid development of activity in certain sunspot groups. The purpose of the program is to test our understanding of the flare process by making public predictions via electronic mail. Neither the exact timing of the flare nor the possibility of emergence of new active regions can be predicted. But high-resolution observations of the magnetic configuration, Ha brightness and structure and other properties of a region enabled us to announce the onset of 15 of 23 major active regions over a two-year period, and 15 of 32 BEARALERTS were followed by this activity. We used high-resolution real-time data available at the Big Bear Solar Observatory (BBSO). The criteria for prediction are given and discussed, along with those for filament eruption. Title: The Orientation of Early Cycle Active Regions and the Polar Coronal Hole Authors: Cannon, A. T.; Marquette, W. H. Bibcode: 1990BAAS...22..873C Altcode: No abstract at ADS Title: Anomalous Orientations of the Polarities In Decaying Active Regions Authors: Cannon, A. T.; Marquette, W. H. Bibcode: 1989BAAS...21..839C Altcode: No abstract at ADS Title: BEARALERTS: A New Program of Flare Prediction Authors: Marquette, W.; Zirin, H. Bibcode: 1989BAAS...21..836M Altcode: No abstract at ADS Title: Development of Noble Liquid Detectors for Gamma Ray Spectroscopy. Authors: Marquette, William H.; Martin, Sara F. Bibcode: 1988SoPh..117..227M Altcode: We describe the decay phase of one of the largest active regions of solar cycle 22 that developed by the end of June 1987. The center of both polarities of the magnetic fields of the region systematically shifted north and poleward throughout the decay phase. In addition, a substantial fraction of the trailing magnetic fields migrated equatorward and south of the leading, negative fields. The result of this migration was the apparent rotation of the magnetic axis of the region such that a majority of the leading polarity advanced poleward at a faster rate than the trailing polarity. As a consequence, this region could not contribute to the anticipated reversal of the polar field. Title: New Information on the Spatial Distribution of Active Regions Authors: Martin, S. F.; Hermans, L. M.; Marquette, W. H. Bibcode: 1981BAAS...13..551M Altcode: No abstract at ADS Title: Factors Related to the Eruption of Quiescent Filaments Authors: Hermans, L. M.; Martin, S. F.; Marquette, W. H. Bibcode: 1980BAAS...12..914H Altcode: No abstract at ADS Title: A Comparison of Solar Cycle 21 with Previous Solar Cycles Authors: Marquette, W. H.; Martin, S. F. Bibcode: 1980BAAS...12..508M Altcode: No abstract at ADS