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Author name code: loughhead
ADS astronomy entries on 2022-09-14
author:"Loughhead, R.E."
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Title: The Solar Granulation
Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.
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.
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Title: Plasma Loops in the Solar Corona
Authors: Bray, R. J.; Cram, L. E.; Durrant, C.; Loughhead, R. E.
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.
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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.
1993SSRv...65..185B Altcode:
No abstract at ADS
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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.
1992Ap&SS.192..160B Altcode:
No abstract at ADS
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Title: Book-Review - Plasma Loops in the Solar Corona
Authors: Bray, R. J.; Cram, L. E.; Durrant, C. J.; Loughhead, R. E.;
Kleczek, J.
1992SoPh..138..423B Altcode:
No abstract at ADS
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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.
1992Sci...255..857C Altcode:
No abstract at ADS
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Title: Book-Review - Plasma Loops in the Solar Corona
Authors: Bray, R. J.; Cram, L. E.; Currant, C. J.; Loughhead, R. E.
1991JBAA..101R.300B Altcode:
No abstract at ADS
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Title: Plasma Loops in the Solar Corona
Authors: Bray, R. J.; Cram, L. E.; Durrant, C.; Loughhead, R. E.
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.
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Title: Plasma loops in the solar corona.
Authors: Bray, R. J.; Cram, L. E.; Durrant, C. J.; Loughhead, R. E.
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.
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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.
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.
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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.
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.
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Title: Book-Review - the Solar Granulation
Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.; Weiss, N. O.
1985SoPh...96..423B Altcode:
No abstract at ADS
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Title: Book-Review - the Solar Granulation - ED.2
Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.; Waddington,
W. G.
1985Obs...105...18B Altcode:
No abstract at ADS
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Title: High-resolution photography of the solar chromosphere. XX
True widths of H-alpha active region loops
Authors: Bray, R. J.; Loughhead, R. E.
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.
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Title: True Shapes of (Post-) Flare and Active Region Loops
Authors: Wang, Jialong; Loughhead, R. E.; Chen, Chuanle
1985spit.conf..455W Altcode:
No abstract at ADS
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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.
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.
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Title: Book-Review - the Solar Granulation
Authors: Bray, R. J.; Loughhead, R. E.
1984Sci...226..571B Altcode:
No abstract at ADS
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Title: Book-Review - the Solar Granulation
Authors: Bray, R. J.; Loughhead, R. E.; Durant, C. J.
1984AExpr...1Q..39B Altcode:
No abstract at ADS
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Title: High-resolution photography of the solar chromosphere. XIX -
Flow velocities along an active region loop
Authors: Loughhead, R. E.; Bray, R. J.
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.
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Title: Book-Review - the Solar Granulation
Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.; Kleczek, J.
1984Ap&SS.103..410B Altcode:
No abstract at ADS
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Title: Book-Review - the Solar Granulation - ED.2
Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.
1984JBAA...94R.196B Altcode:
No abstract at ADS
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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.
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.
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Title: Isophotes of a large granule
Authors: Bray, R. J.; Loughhead, R. E.
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.
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Title: Book-Review - the Solar Granulation
Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.; Nordlund, A.
1984SSRv...39R.222B Altcode:
No abstract at ADS
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Title: Book-Review - the Solar Granulation
Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.
1984S&T....68T.426B Altcode:
No abstract at ADS
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Title: The solar granulation Durrant.
Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.
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.
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Title: Book-Review - the Solar Granulation
Authors: Bray, R. J.; Loughhead, R. E.; Durrant, C. J.
1984AExpr...1S..39B Altcode:
No abstract at ADS
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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.
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.
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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.
1983SoPh...88Q.391L Altcode:
No abstract at ADS
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Title: High-resolution photography of the solar chromosphere. XVI. Hα
contrast profiles of active region loops.
Authors: Bray, R. J.; Loughhead, R. E.
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<SUP>−1</SUP> upward to 78 km
s<SUP>−1</SUP> downward. However, more accurate profiles and a more
rigorous theory are needed to confirm the validity of this application
of the cloud model.
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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.
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.
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Title: Geometry of H-alpha active region loops observed on the
solar disk
Authors: Chen, C. -L.; Loughhead, R. E.
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.
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Title: Bright Dots Inside Sunspots
Authors: Thiessen, G.; Loughhead, R. E.; Bray, R. J.; Tappere, E. J.
1980S&T....59..120T Altcode:
No abstract at ADS
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Title: Book-Review - Sunspots
Authors: Bray, R. J.; Loughhead, R. E.
1980S&T....59..241B Altcode:
No abstract at ADS
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Title: Book-Review - Sunspots
Authors: Bray, R. J.; Loughhead, R. E.
1980Sci...208..428B Altcode:
No abstract at ADS
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Title: Improved observations of sunspot umbral dots.
Authors: Loughhead, R. E.; Bray, R. J.; Tappere, E. J.
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.
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Title: Sunspots.
Authors: Bray, R. J.; Loughhead, R. E.
1979suns.book.....B Altcode:
No abstract at ADS
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Title: On the possibility of measuring stellar convection parameters.
Authors: Bray, R. J.; Loughhead, R. E.
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.
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Title: A convective correction to measured solar wavelengths.
Authors: Bray, R. J.; Loughhead, R. E.
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.
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Title: Fourier transforms applied to the contrast profile method of
measuring vector magnetic fields.
Authors: Loughhead, R. E.; Bray, R. J.
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.
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Title: Instrumental profile of a triple Fabry-Perot interferometer
for use in solar spectroscopy.
Authors: Loughhead, R. E.; Bray, R. J.; Brown, N.
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.
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Title: A new determination of the granule/ intergranule contrast.
Authors: Bray, R. J.; Loughhead, R. E.
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.
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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.
1977SoPh...55..274B Altcode:
No abstract at ADS
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Title: Visibility of magnetic features on filtergrams and
spectroheliograms.
Authors: Loughhead, R. E.; Bray, R. J.
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.
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Title: Convective velocities derived from granule contrast profiles
in Fe i λ 6569.2
Authors: Bray, R. J.; Loughhead, R. E.; Tappere, E. J.
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.
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Title: Visibility of the photospheric granulation in Fe i λ 6569.2
Authors: Loughhead, R. E.; Bray, R. J.
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.
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Title: Review of 'The Solar Chromosphere'
Authors: Bray, R. J.; Loughhead, R. E.
1975Obs....95..148B Altcode:
No abstract at ADS
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Title: High-Resolution Photography of the Solar Chromosphere. XIV:
Morphology of Sunspots at the Chromospheric Level
Authors: Loughhead, R. E.
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.
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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.
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.
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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.
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.
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Title: The solar chromosphere
Authors: Bray, R. J.; Loughhead, R. E.
1974soch.book.....B Altcode: 1974QB528.B7.......
No abstract at ADS
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Title: High-Resolution Photography of the Solar Chromosphere. XI:
H&alpha Constrast Profiles of Mottles near the Limb
Authors: Loughhead, R. E.
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.
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Title: High-Resolution Photography of the Solar Chromosphere. IX:
Limb Observations of High Spectral Purity
Authors: Loughhead, R. E.; Tappere, E. J.
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.
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Title: High-Resolution Photography of the Solar Chromosphere. VII:
Structure of the Low Chromosphere
Authors: Loughhead, R. E.
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.
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.
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.
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.
1968ZA.....68..416B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The solar granulation
Authors: Bray, R. J.; Loughhead, R. E.
1967sogr.book.....B Altcode: 1967QB539.B68......
No abstract at ADS
---------------------------------------------------------
Title: Statistics of Solar Seeing
Authors: Loughhead, R. E.; Bray, R. J.
1966ZA.....63..101L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Sunspots
Authors: Bray, R. J.; Loughhead, R. E.
1964suns.book.....B Altcode: 1964QB525.B78......
No abstract at ADS
---------------------------------------------------------
Title: Isophotal Contour Maps of Sunspots
Authors: Bray, R. J.; Loughhead, R. E.
1962AuJPh..15..482B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Phenomena Accompanying the Birth of Sunspot Pores
Authors: Loughhead, R. E.; Bray, R. J.
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.
1961AuJPh..14...14B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Granulation near the Extreme Solar Limb
Authors: Loughhead, R. E.; Bray, R. J.
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.
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.
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.
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.
1959AuJPh..12...97L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of Changes in the Photospheric Granules
Authors: Bray, R. J.; Loughhead, R. E.
1958AuJPh..11..507B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Lifetime of Sunspot Penumbra Filaments
Authors: Bray, R. J.; Loughhead, R. E.
1958AuJPh..11..185B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: The Wilson Effect in Sunspots
Authors: Loughhead, R. E.; Bray, R. J.
1958AuJPh..11..177L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: High Resolution Cinematography of the Solar Photosphere
Authors: Loughhead, R. E.; Burgess, V. R.
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.
1957AuJPh..10..483L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Bright regions in sunspots
Authors: Bray, R. J.; Loughhead, R. E.
1957Obs....77..201B Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Twisted Magnetic Fields in Conducting Fluids
Authors: Dungey, J. W.; Loughhead, R. E.
1954AuJPh...7....5D Altcode:
No abstract at ADS
