Author name code: loughhead ADS astronomy entries on 2022-09-14 author:"Loughhead, R.E." ------------------------------------------------------------------------ Title: The Solar Granulation Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J. Bibcode: 2009sogr.book.....B Altcode: Preface; Acknowledgements; 1. Historical introduction; 2. The morphology, evolution and dynamics of the granulation and supergranulation; 3. An introduction to the theory of convection; 4. The theory of astrophysical convection; Interpretation of the granulation and spuergranulation; References; Name index; Subject index. Title: Plasma Loops in the Solar Corona Authors: Bray, R. J.; Cram, L. E.; Durrant, C.; Loughhead, R. E. Bibcode: 2006plsc.book.....B Altcode: 1. Historical introduction; 2. Cool loops: observed properties; 3. Hot loops: observed properties; 4. Flare loops: observed properties; 5. Structure, dynamics and heating of loops; 6. The plasma loop model of the coronae of the sun and stars. Title: Book-Review - Plasma Loops in the Solar Corona Authors: Bray, B. J.; Cram, L. E.; Durrant, C. J.; Loughhead, R. E.; Cheng, C. C. Bibcode: 1993SSRv...65..185B Altcode: No abstract at ADS Title: Book Review: Plasma loops in the solar corona / Cambridge U Press, 1991 Authors: Cram, L. E.; Durrent, C. J.; Loughhead, R. E.; Hartquist, T. W. Bibcode: 1992Ap&SS.192..160B Altcode: No abstract at ADS Title: Book-Review - Plasma Loops in the Solar Corona Authors: Bray, R. J.; Cram, L. E.; Durrant, C. J.; Loughhead, R. E.; Kleczek, J. Bibcode: 1992SoPh..138..423B Altcode: No abstract at ADS Title: Book Review: Plasma loops in the solar corona / Cambridge U Press, 1991 Authors: Cram, L. E.; Currant, C. J.; Loughhead, R. E.; Zweibel, E. Bibcode: 1992Sci...255..857C Altcode: No abstract at ADS Title: Book-Review - Plasma Loops in the Solar Corona Authors: Bray, R. J.; Cram, L. E.; Currant, C. J.; Loughhead, R. E. Bibcode: 1991JBAA..101R.300B Altcode: No abstract at ADS Title: Plasma Loops in the Solar Corona Authors: Bray, R. J.; Cram, L. E.; Durrant, C.; Loughhead, R. E. Bibcode: 1991plsc.book.....B Altcode: 1991QB529.P57...... A comprehensive account of the properties of plasma loops, the fundamental structural elements of the solar corona. Plasma loops cover a wide range of sizes and range in temperature from tens of thousands to millions of degrees. They not only define the structure of individual active regions but connect different active regions--even across the solar equator. Loops also play an integral and decisive role in the enormous solar explosions called flares. Over recent years a wealth of space and ground-based observations of loops has been obtained in various widely-spaced regions of the electromagnetic spectrum. In this book the authors have selected the best observational material from the literature on which to base a detailed account of the properties of flare and non-flare loops. The book also explores the larger implications of the loop structures for our understanding of solar and stellar coronae. The text is enhanced by a large number of illustrations and unique and beautiful photographs obtained from the ground and from space. Title: Plasma loops in the solar corona. Authors: Bray, R. J.; Cram, L. E.; Durrant, C. J.; Loughhead, R. E. Bibcode: 1991CAS....18.....B Altcode: This book presents the first comprehensive account of the properties of plasma loops, the fundamental structural elements of the solar corona. Plasma loops not only define the structure of individual active regions but connect different active regions. Loops also play an integral and decisive role in solar flares. The authors have selected the best observational material from the literature on which to base a detailed account of the properties of flare and non-flare loops. The book also explores the larger implications of the loop structures in our understanding of solar and stellar coronae. The text is enhanced by a large number of illustrations and photographs obtained from the ground and from space. Title: High-Resolution Photography of the Solar Chromosphere. XXIII. Direct Measurement of the Optical Thickness of H alpha Solar Loops Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1986ApJ...301..989B Altcode: A method has been devised which, under appropriate observational circumstances, enables a direct determination to be made of the optical thickness t(L) of high-rising H-alpha solar loops observed on the disk. It is applicable to both bright and dark loops and requires no knowledge of the source function in the loop; it is best adapted to optically thin ones. The technique has been successfully applied to four loops observed under various circumstances, giving values of t(L) ranging from 0.06 to 1.3. It is not restricted to H-alpha loops but, in principle, could also be applied to chromospheric and coronal fine structures observed in the visible, EUV, and X-ray regions. Title: High-resolution photography of the solar chromosphere. XXI Determination of the physical conditions in an H-alpha active-region loop Authors: Loughhead, R. E.; Bray, R. J.; Wang, J. -L. Bibcode: 1985ApJ...294..697L Altcode: Values of the electron temperature, electron density, gas density, gas pressure, degree of hydrogen ionization, and other physical conditions are determined at seven locations along the axis of an H-alpha active-region loop observed on the solar disk. Combining these data with earlier results, a fairly complete description is presented of the true geometry, flow velocities, and thermodynamic conditions in such a loop at one moment of time. The physical conditions show a marked variation along the loop. The variations in density and pressure exhibit a wavelike nature, with an apparent wavelength of some 50,000-60,000 km. The results offer the prospect of putting observational constraints on theoretical models of coronal loops and of identifying the types of flows and waves present. Title: Book-Review - the Solar Granulation Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.; Weiss, N. O. Bibcode: 1985SoPh...96..423B Altcode: No abstract at ADS Title: Book-Review - the Solar Granulation - ED.2 Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.; Waddington, W. G. Bibcode: 1985Obs...105...18B Altcode: No abstract at ADS Title: High-resolution photography of the solar chromosphere. XX True widths of H-alpha active region loops Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1985A&A...142..199B Altcode: The true widths are measured of two very thin (sub-arcsec) loops observed on the disk at Hα+1.0 Å at a height of several thousand kilometers. A realistic deconvolution procedure is applied to correct for the combined instrumental profile of telescope and atmosphere. This yields upper and lower limits to the true widths, corresponding to the possible range in the magnitude of the effective aperture of the telescope (Fried parameter) at the moment of observation. Title: True Shapes of (Post-) Flare and Active Region Loops Authors: Wang, Jialong; Loughhead, R. E.; Chen, Chuanle Bibcode: 1985spit.conf..455W Altcode: No abstract at ADS Title: High-resolution photography of the solar chromosphere. XXII - Relationship between the H-alpha and hard X-ray emission from the 3B/X 1.5 flare of 13 May 1981 Authors: Loughhead, R.; Blows, G.; Wang, J. -L. Bibcode: 1985PASJ...37..619L Altcode: Comparison of Hinotori observations of the hard X-ray burst from the large, two-ribbon flare of 13 May 1981 with high-resolution Hα photographs taken at the Culgoora Observatory reveals that the onset of the burst was accompanied by the development of two bright Hα kernels in the penumbrae of two sunspots of opposite magnetic polarity. The kernels identify the chromospheric footpoints of a large, stationary coronal loop containing the source of the hard X-rays. A study of the likely geometry of the loop indicates that the source was located almost directly above the spot associated with the brighter of the two kernels, at a height of some 66,000 km. The umbra of this spot displayed marked changes in appearance during and immediately following the final phase of the hard X-ray burst. Title: Book-Review - the Solar Granulation Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1984Sci...226..571B Altcode: No abstract at ADS Title: Book-Review - the Solar Granulation Authors: Bray, R. J.; Loughhead, R. E.; Durant, C. J. Bibcode: 1984AExpr...1Q..39B Altcode: No abstract at ADS Title: High-resolution photography of the solar chromosphere. XIX - Flow velocities along an active region loop Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1984ApJ...283..392L Altcode: True flow velocities along the central axis of an active region loop have been determined for the first time. This has been done by combining measurement of the line-of-sight velocity at a number of points with a mathematical technique for reconstructing the true shape, size, and orientation of a (tilted) loop observed on the solar disk. The loop material is found to rise from the surface along one leg with an increasing upward velocity despite the retarding effect of gravity. Descending material in the other leg suffers a retarding force and does not attain the velocity of free fall. The derived velocities are supersonic at all points measured; the Mach number exceeds 5 at one location. Title: Book-Review - the Solar Granulation Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.; Kleczek, J. Bibcode: 1984Ap&SS.103..410B Altcode: No abstract at ADS Title: Book-Review - the Solar Granulation - ED.2 Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J. Bibcode: 1984JBAA...94R.196B Altcode: No abstract at ADS Title: High Resolution Photography of the Solar Chromosphere - Part 18 - Axial Tilt of Hα Loops Observed on the Disk Authors: Loughhead, R. E.; Chen, C. -L.; Wang, J. -L. Bibcode: 1984SoPh...92...53L Altcode: A method is described for reconstructing the true geometry of a solar loop observed on the disk which takes account of tilt in its own plane. Reconstructions of three Hα loops yield small tilt angles (≲14°) and provide further evidence that Hα loops show a close correspondence to the field lines of a magnetic dipole. The method offers new opportunities for exploring the physics of individual solar loops. Title: Isophotes of a large granule Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1984A&A...133..409B Altcode: Isophotal contour maps of a single large photospheric granule are presented, derived from three high-quality photographs taken within a short time interval. The brightness distribution is markedly asymmetrical, both the brightest and darkest points being located away from the geometrical centre. The maps show real structural features on a scale down to ≡0arcsec.5, but smaller distortions in the isophotes are artifacts due to residual seeing effects. Title: Book-Review - the Solar Granulation Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.; Nordlund, A. Bibcode: 1984SSRv...39R.222B Altcode: No abstract at ADS Title: Book-Review - the Solar Granulation Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J. Bibcode: 1984S&T....68T.426B Altcode: No abstract at ADS Title: The solar granulation Durrant. Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J. Bibcode: 1984cup..book.....B Altcode: A comprehensive account of observational and theoretical knowledge of solar granulation is presented. A historical introduction to the solar granulation is given, and the morphology, evolution, and dynamics of granulation and supergranulation are discussed. The theory of convection is introduced, and the theory of astrophysical convection is addressed. Finally, the interpretation of granulation and supergranulation is considered. Title: Book-Review - the Solar Granulation Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J. Bibcode: 1984AExpr...1S..39B Altcode: No abstract at ADS Title: High-resolution photography of the solar chromosphere. XVII Geometry of H-alpha flare loops observed on the disk Authors: Loughhead, R. E.; Wang, J. -L.; Blows, G. Bibcode: 1983ApJ...274..883L Altcode: A geometrical technique is described for reconstructing the true shape of a solar loop observed on the disk. The method is based on the assumptions that (1) the loop's central axis lies in a plane, (2) its footpoints can be located, and (3) it is symmetrical in its own plane about an axis at right angles to the line joining the footpoints. The method is used to reconstruct three Hα (post-) flare loops in arcades visible in the declining stage of a large, two-ribbon flare. They are found to lie in planes nearly normal to the solar surface and to have heights in the range 44,500 - 50,000 km. The reconstructed central axis of each loop is compared with the magnetic field lines passing through the footpoints and apex for a point magnetic dipole and Pneuman's magnetic reconnection model of a two-ribbon flare. Title: Erratum: Optical Counterpart of the Radio Event Accompanying the 3B Flare of 13 May 1981 Authors: Loughhead, R. E.; Wang, Jia-Long; Duncan, R. A. Bibcode: 1983SoPh...88Q.391L Altcode: No abstract at ADS Title: High-resolution photography of the solar chromosphere. XVI. Hα contrast profiles of active region loops. Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1983SoPh...85..131B Altcode: High-resolution filtergrams of an active region loop taken at seven wavelengths in Hα have been used to derive the contrast at eleven locations along its length as a function of wavelength. With an appropriate choice of parameters, theoretical curves calculated on the basis of the `cloud" model give a reasonable fit to the observed contrast profiles. The inferred line-of-sight components of the mass velocity range from 27 km s−1 upward to 78 km s−1 downward. However, more accurate profiles and a more rigorous theory are needed to confirm the validity of this application of the cloud model. Title: Optical counterpart of the radio event accompanying the 3B flare of 13 May 1981 Authors: Loughhead, R. E.; Duncan, R. A.; Wang, J. -L. Bibcode: 1983SoPh...83..257L Altcode: Excepting intermittent type III activity, all the radio events over the frequency range 8-8000 MHz accompanying the initial stage of the 3B flare of 13 May, 1981 had their onset in a 2-min interval immediately preceding the peak of an impulsive Hα brightening (kernel) well away from the main flare. This kernel is identified as one footpoint of a loop of magnetic flux whose other end terminated in a transient brightening in an adjacent active region. Title: Geometry of H-alpha active region loops observed on the solar disk Authors: Chen, C. -L.; Loughhead, R. E. Bibcode: 1983PASA....5..204C Altcode: 1983PASAu...5..204C The technique devised by Loughhead et al. (1983) is used here to reconstruct two large dark loops of the type ordinarily found in active regions in the absence of flares. The loops chosen for reconstruction belonged to a complex loop system which had a lifetime of at least 5-6 hr. No flares occurred in the active region during the period of observation, but there was a marked resurgence of activity some hours later. The reconstructions of the loops are presented along with the values of the parameters characterizing each loop and the orientation of its plane with respect to the solar surface. Both loops reach heights close to the typical value of 50,000 km quoted by Chiuderi (1981) for coronal loops observed at EUV and X-ray wavelengths. Title: Bright Dots Inside Sunspots Authors: Thiessen, G.; Loughhead, R. E.; Bray, R. J.; Tappere, E. J. Bibcode: 1980S&T....59..120T Altcode: No abstract at ADS Title: Book-Review - Sunspots Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1980S&T....59..241B Altcode: No abstract at ADS Title: Book-Review - Sunspots Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1980Sci...208..428B Altcode: No abstract at ADS Title: Improved observations of sunspot umbral dots. Authors: Loughhead, R. E.; Bray, R. J.; Tappere, E. J. Bibcode: 1979A&A....79..128L Altcode: New observations have been obtained of the umbrae of 18 spots near the solar disk center using the CSIRO 30-cm refractor in its photospheric mode under seeing-monitor control (Bray and Loughhead, 1977). The telescope was programmed to take sequences of photographs with exposures ranging (for a large spot) up to 13 times that for the photosphere in order to capture the fine detail in all parts of each umbra. Under normal circumstances the level of scattered light (instrumental plus atmospheric) in the Culgoora Telescope has been found to be less than 0.9% (Bray and Loughhead, 1977). For the umbral observations it was further reduced by placing small diaphragms at the prime focus in the manner described by Bray and Loughhead, 1964). The umbral dot structure is discussed. The observations made show that umbral dots virtually cover the umbra, including the darkest regions of large spots, where the low contrast of the dot pattern has hitherto hindered its observations. Title: Sunspots. Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1979suns.book.....B Altcode: No abstract at ADS Title: On the possibility of measuring stellar convection parameters. Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1978PASP...90..609B Altcode: The detailed knowledge of solar convection now available is used to evaluate the possibility of deriving some of the surface convection parameters of other stars from line-profile measurements. A theory is outlined for computing integrated line profiles with convection, rotation, and limb darkening. This theory is employed to calculate line profiles for rotating convecting stars of the solar class for values of equatorial v sin i ranging from 0 to 10 km/s. Fourier sine transforms for solar-class stars are examined, and applications to stars not of the solar class are discussed. Several possible sources of line asymmetry are identified. Title: A convective correction to measured solar wavelengths. Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1978ApJ...224..276B Altcode: Convective motions in the solar photosphere associated with the granulation introduce an asymmetry into a spatially averaged line profile and shift the wavelength of the center of gravity to the violet. This shift leads to a significant error in absolute wavelength determinations based on spatially averaged spectra. The magnitude of the error depends on a large number of granulation and line profile parameters and must be computed separately for each line. Calculations based on modern values of the various parameters lead to a violet shift at the center of the solar disk of about 0.0035 A for the center of gravity of the photospheric line of Fe I at 6569.2 A. The correction to the Oxford measurements of this line reduces the apparent discrepancy between the observed redshift and the predicted gravitational shift by one-half. Consideration of both the Oxford and Georgetown results leads to the conclusion that there is no convincing evidence at the present time for a real discrepancy. Title: Fourier transforms applied to the contrast profile method of measuring vector magnetic fields. Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1978PASP...90..230L Altcode: The contrast profile method of measuring strong magnetic fields (Loughhead and Bray 1976) offers the advantages of high spatial resolution and freedom from the saturation effects encountered with the conventional magnetograph. This paper explores theoretically the extent to which the application of Fourier transforms to magnetic contrast profile data can facilitate the derivation of the various field and velocity parameters. For a stationary solar feature, Fourier transforms offer no advantage. However, for a moving feature the Fourier sine transform provides a simpler and more sensitive means of inferring the magnitude and direction of the field and the line-of-sight velocity than the original contrast data. Title: Instrumental profile of a triple Fabry-Perot interferometer for use in solar spectroscopy. Authors: Loughhead, R. E.; Bray, R. J.; Brown, N. Bibcode: 1978ApOpt..17..415L Altcode: A universal filter for use in solar spectroscopy is under development, consisting of a computer-controlled triple Fabry-Perot interferometer. The paper explores the extent to which the performance of such a filter is degraded by off-axis effects under the intended conditions of use. Computed instrumental profiles for both on- and off-axis cases are presented. The calculated bandwidths range from 0.21 A to 0.047 A at eight wavelengths of interest in the visible region of the spectrum. Title: A new determination of the granule/ intergranule contrast. Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1977SoPh...54..319B Altcode: A new determination of the granule/intergranule contrast is described, based on high-quality photographs taken with the Culgoora refractor operating in its photospheric mode. The measurements are corrected for scattered light and for spatial smearing due to telescope and atmosphere. The contrast calculated on the basis of the Utrecht Reference Photosphere lies just outside the range of possible values permitted by the present observations, 0.76 ⩽ C⩽ 0.81 at λ5500. New determinations of the mean cell size of the granulation pattern (= 1″.9 of arc) and of the distribution of cell sizes are also presented. Title: Erratum: "Convective velocities derived from granule contrast profiles in Fe I lambda 6569.2" [Sol. Phys., Vol. 49, p. 3 - 18 (1976)]. Authors: Bray, R. J.; Loughhead, R. E.; Tappere, E. J. Bibcode: 1977SoPh...55..274B Altcode: No abstract at ADS Title: Visibility of magnetic features on filtergrams and spectroheliograms. Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1976SoPh...50..297L Altcode: An expression is derived for the contrast variation of a hypothetical magnetic element observed with a tunable monochromatic filter or spectroheliograph in a triplet Zeeman line. The theory is valid for a magnetic field of arbitrary strength and direction and for polarizing and non-polarizing optics. Numerical results are presented for both a stationary and a moving magnetic element over a range of field strengths and directions. They provide a simple diagnostic means of inferring the presence or, alternatively, the absence of strong fields, such as the kilogauss network fields postulated by Stenflo and others on the basis of indirect evidence. The proposed method of measuring strong fields is capable of very high spatial resolution and is free of the saturation effects encountered in the conventional magnetograph. Title: Convective velocities derived from granule contrast profiles in Fe i λ 6569.2 Authors: Bray, R. J.; Loughhead, R. E.; Tappere, E. J. Bibcode: 1976SoPh...49....3B Altcode: A new determination of the granular and intergranular velocities is described, based on a new approach. The method involves measurement of the granule/intergranule contrast as a function of wavelength on a sequence of filtergrams taken with the CSIRO computer-controlled 1/8 Å filter in the photospheric line Fe I λ6569.2. A procedure based on a simple but realistic morphological model of the granulation pattern is used to correct for spatial smearing. The effects of spectral smearing and of scattered light are also taken into account. Title: Visibility of the photospheric granulation in Fe i λ 6569.2 Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1975SoPh...45...35L Altcode: High-quality photographs of the granulation obtained at seven wavelengths in the Fe I line λ 6569.2 are presented. The granule contrast attains a maximum considerably exceeding the continuum value around Fe+0.05 to Fe+0.10 Å; individual granules remain easily visible to within 5″ of the limb. At line centre only remnants of the granulation pattern are discernible. Title: Review of 'The Solar Chromosphere' Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1975Obs....95..148B Altcode: No abstract at ADS Title: High-Resolution Photography of the Solar Chromosphere. XIV: Morphology of Sunspots at the Chromospheric Level Authors: Loughhead, R. E. Bibcode: 1974SoPh...38...77L Altcode: A detailed description is given of the morphology of two isolated, fairly regular sunspots based on high-resolution observations obtained at seven wavelengths in the Hα line with a spectral purity and discrimination not hitherto achieved. Photometric traces across one of the spots confirm an earlier conclusion that the umbra-penumbra boundary is diffuse near the line centre but sharp in the wings. They also reveal considerable changes in the intensity contours of a sunspot from line centre to wings. Title: High-Resolution Photography of the Solar Chromosphere. XII: An Attempt to Measure Vertical Velocities of Hα Bright Mottles beyond Limb Authors: Loughhead, R. E. Bibcode: 1974SoPh...35...55L Altcode: Measurements have been made of the heights of seven bright mottles photographed beyond the limb on sequences of broad-band Hα filtergrams. They reveal no evidence of a systematic upward or downward motion persisting throughout the lifetime of a mottle, and in no case does the observed change in height exceed 1″ (725 km) over the period of observation. On the other hand, the possibility cannot be excluded that the bright mottles execute vertical oscillations with velocities comparable to those recently deduced from Hα contrast profile analyses by Grossmann-Doerth and von Uexküll (1971) and Bray (1973) provided the periods do not exceed a few tens of seconds. Title: High-Resolution Photography of the Solar Chromosphere. XV: Preliminary Observations in Fe I λ6569.2 Authors: Bray, R. J.; Loughhead, R. E.; Tappere, E. J. Bibcode: 1974SoPh...39..323B Altcode: High-quality photographs of the quiet and enhanced network have been obtained at the centre of Fe I λ6569.2 and in the nearby continuum, using a 1/8 Å filter. In agreement with Dunn and Zirker, the photospheric granules are noticeably smeared in the neighbourhood of the enhanced network. Nevertheless, many of the bright network elements are co-spatial with individual (smeared) photospheric granules. Title: The solar chromosphere Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1974soch.book.....B Altcode: 1974QB528.B7....... No abstract at ADS Title: High-Resolution Photography of the Solar Chromosphere. XI: H&alpha Constrast Profiles of Mottles near the Limb Authors: Loughhead, R. E. Bibcode: 1973SoPh...29..327L Altcode: Curves showing the contrast of individual bright and dark mottles near the limb at various wavelengths in the Hα line have been plotted from observations made through a 1/8 Å filter. The results cannot be explained in terms of the `cloud' model of mottles proposed by Beckers (1964) and employed with some success by Grossmann-Doerth and von Uexküll (1971) and Bray (1973) to interpret the profiles of bright and dark mottles near the centre of the disk. Title: High-Resolution Photography of the Solar Chromosphere. IX: Limb Observations of High Spectral Purity Authors: Loughhead, R. E.; Tappere, E. J. Bibcode: 1971SoPh...19...44L Altcode: High-quality photographs of the solar limb and neighbouring regions of the disk at various wavelengths in the Hα line have been obtained through a tunable 1/8 Å filter used in tandem with a 1 Å Halle filter to eliminate parasitic light. The new observations throw further light on (a) the reappearance of the photospheric limb in the wings of Hα, and (b) the dark band lying immediately above the photospheric limb described by Loughhead (1969) and Nikolsky (1970). On the other hand, taken in isolation they add very little new information bearing on the question of the identification of spicules with disk structures. Title: High-Resolution Photography of the Solar Chromosphere. VII: Structure of the Low Chromosphere Authors: Loughhead, R. E. Bibcode: 1969SoPh...10...71L Altcode: High-resolution observations of the low chromosphere beyond the limb at the centre of the Hα line reveal the existence of two types of fine structure whose presence has hitherto been unobserved: (1) small bright features which show a close correspondence in properties with the bright mottles on the disk and are unequivocally identifiable as the latter seen beyond the limb; and (2) a narrow dark band lying immediately above the photospheric limb whose physical significance is not yet clear. Title: High-Resolution Photography of the Solar Chromosphere Authors: Loughhead, R. E. Bibcode: 1968SoPh....5..489L Altcode: High-quality Hα photographs of the solar chromosphere reveal the presence around isolated sunspots of a pattern of elongated dark elements (fibrils) bearing a strong resemblance to a greatly enlarged version of the white-light penumbra. Individual fibrils have a representative length of some 25″ of arc (18000 km) and a typical separation of 2-3″. Comparison of pairs of photographs separated by intervals ranging from 0.5 min to 42 min shows that the fibrils undergo continual changes in brightness, size, and shape; their average lifetime is about 17 min. The question is raised whether the fibril structure around a spot is related in any way to the observed inflow of material from the surrounding chromosphere (Evershed effect). Title: High-Resolution Photography of the Solar Chromosphere. III: The Fine Structure of a Class I Flare Authors: Loughhead, R. E. Bibcode: 1968SoPh....4..422L Altcode: No abstract at ADS Title: High-Resolution Photography of the Solar Chromosphere. I: The 30-cm Refractor of the C. S. I. R. O. Solar Observatory Authors: Loughhead, R. E.; Bray, R. J.; Tappere, E. J.; Winter, J. G. Bibcode: 1968SoPh....4..185L Altcode: A new telescope designed for high-resolution photography of the chromosphere is described. It is mounted in the open air on a 15-m tower and is provided with air suction shields to cool all surfaces exposed to the sun's rays. The best moments for photography are selected by a seeing monitor. The highest resolution so far attained is 0″. 75 of arc, compared with a theoretical resolution limit at Hα of 0″. 55. Title: Buchbesprechungen über: The Solar Granulation. (Ref. E. H. SCHRÖTER) Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1968ZA.....68..416B Altcode: No abstract at ADS Title: The solar granulation Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1967sogr.book.....B Altcode: 1967QB539.B68...... No abstract at ADS Title: Statistics of Solar Seeing Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1966ZA.....63..101L Altcode: No abstract at ADS Title: Sunspots Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1964suns.book.....B Altcode: 1964QB525.B78...... No abstract at ADS Title: Isophotal Contour Maps of Sunspots Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1962AuJPh..15..482B Altcode: No abstract at ADS Title: Phenomena Accompanying the Birth of Sunspot Pores Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1961AuJPh..14..347L Altcode: No abstract at ADS Title: Facular Granule Lifetimes determined with a Seeing-monitored Photoheliograph Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1961AuJPh..14...14B Altcode: No abstract at ADS Title: Granulation near the Extreme Solar Limb Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1960AuJPh..13..738L Altcode: No abstract at ADS Title: The Lifetime and Cell Size of the Granulation in Sunspot Umbrae Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1960AuJPh..13..139L Altcode: No abstract at ADS Title: High Resolution Observations of the Granular Structure of Sunspot Umbrae Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1959AuJPh..12..320B Altcode: No abstract at ADS Title: A "seeing monitor" to aid solar observation Authors: Bray, R. J.; Loughhead, R. E.; Norton, D. G. Bibcode: 1959Obs....79...63B Altcode: No abstract at ADS Title: Observations of Faculae bordering Small Sunspots near the Limb Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1959AuJPh..12...97L Altcode: No abstract at ADS Title: Observations of Changes in the Photospheric Granules Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1958AuJPh..11..507B Altcode: No abstract at ADS Title: The Lifetime of Sunspot Penumbra Filaments Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1958AuJPh..11..185B Altcode: No abstract at ADS Title: The Wilson Effect in Sunspots Authors: Loughhead, R. E.; Bray, R. J. Bibcode: 1958AuJPh..11..177L Altcode: No abstract at ADS Title: High Resolution Cinematography of the Solar Photosphere Authors: Loughhead, R. E.; Burgess, V. R. Bibcode: 1958AuJPh..11...35L Altcode: No abstract at ADS Title: The Association of Solar Radio Bursts of Spectral Type III with Chromospheric Flares Authors: Loughhead, R. E.; Roberts, J. A.; McCabe, Marie K. Bibcode: 1957AuJPh..10..483L Altcode: No abstract at ADS Title: Bright regions in sunspots Authors: Bray, R. J.; Loughhead, R. E. Bibcode: 1957Obs....77..201B Altcode: No abstract at ADS Title: Twisted Magnetic Fields in Conducting Fluids Authors: Dungey, J. W.; Loughhead, R. E. Bibcode: 1954AuJPh...7....5D Altcode: No abstract at ADS