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Article
High-resolution photography of the solar chromosphere
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°) an...
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Article
High-resolution photography of the solar chromosphere
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 ch...
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Article
Optical counterpart of the radio event accompanying the 3B flare of 13 May 1981
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...
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Article
A new determination of the granule/intergranule contrast
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...
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Article
Visibility of magnetic features on filtergrams and spectroheliograms
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 magn...
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Article
Convective velocities derived from granule contrast profiles in Fe i λ 6569.2
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 seq...
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Article
Visibility of the photospheric granulation in Fei λ 6569.2
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 ...
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Article
High-resolution photography of the solar chromosphere
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 discrimi...
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Article
High-resolution photography of the solar chromosphere
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 pers...
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Article
High-resolution photography of the solar chromosphere
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 g...
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Article
High-resolution photography of the solar chromosphere
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 explain...
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Article
High-resolution photography of the solar chromosphere
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...
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Article
High-resolution photography of the solar chromosphere
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 brig...
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Article
High-resolution photography of the solar chromosphere
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 o...
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Article
High-resolution photography of the solar chromosphere
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Article
High-resolution photography of the solar chromosphere
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...
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Article
‘Turbulence’ and the Photospheric Granulation
EARLY high-resolution photographs of the solar photosphere showed a well-defined pattern of bright granules with diameters lying mostly in the range 1–2 sec. of arc. The similarity of this structure to laborat...
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Article
Correlation Patterns in the Chromospheric Granulation
UBEROI1 has recently discussed a simple method of measuring the spatial correlation of the brightness fluctuations between neighbouring regions in the solar photosphere. He pointed out that, if two identical enla...
