[en] Fabry-Perot interferometric observations of the lambda 5303 A corona line on 22 September, 1968 were carried out. There are many elements of the interferometric rings with considerable line of sight velocities. The influence on the results of the changes in the brightness of the monochromatic and white-light corona were discussed. (Auth.)

[en] The spectra of fluorescence and fluorescence excitation of tetraazachlorin and tetraazabacteriochlorin substituted at the reduced pyrrole rings have been investigated at 290 and 77 K; the fluorescence quantum yield and life time have been measured at 290 K; the fluorescence polarization spectra have been obtained at 77 K. Quantum-chemical calculations have been performed for a series of porphin derivatives: porphin-chlorin-bacteriochlorin-tetraazaporphin (porphyrazine)-tetraazachlorin- tetraazabacteriochlorin by the CNDO/S method with the use of molecular geometry acquired by the AM1 and PM3 optimization. The visible and UV absorption spectra and the fluorescence polarization spectra are adequately described by the CNDO/S calculation results, as well as the spectral changes in the series porphyrazine-tetraazachlorin-tetraazabacteriochlorin and from bacteriochlorin to tetraazabacteriochlorin. Strong quenching of fluorescence on the pyrrole rings reduction in the porphyrazine macrocycle has been found. It is shown that this quenching cannot be wholly explained by the increase in the rate constant of the S₁→S₀ internal conversion which may be due to the lowering of the S₁ level. Supposedly, the increase in the rate constant of the S₁→T₁ intersystem crossing is due to participation of intermediate triplet levels in this process

[en] In the 3200-5600 A region the limb-darkening coefficients of the solar disk in the integral spectrum (i.e. in the continuum with all the absorption lines) have been calculated. In the calculations, the continuum limb-darkening coefficients and the estimates for the behaviour of lines of different intensity categories in the transition from the centre of the disk to the limb have been used. The complete sums of equivalent widths of all the lines in centre and at the limb, and separate ones for strong (the equivalent width is more than 250 m A) lines are given. The limb-darkening coefficients have been tabulated. Their root-mean-square error is estimated to be about 3-5 per cent

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[en] The energy distribution of the solar spectrum in the region 255-1060 nm has been obtained as a weighted average of the most reliable measurements. This energy distribution is recommended as a standard. The reliability of each series of measurements was examined by objective criterion: by agreement of colour indices in the 13-colour system of Johnson-Mitchell of each series under examination with the normal colour indices of the solar-type (G2 V) stars. Solar photometers abservations were analysed and as a result an independent series of solar spectrophotometric data was obtained

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[en] An active region emission loop has been reconstructed, its true form and size have been determined. The loop proved to be almost vertical to the solar surface and only slightly inclined in its own plane. The loop matter has been found to rize from the solar surface along one leg with velocities 105-35 km/s and to descend in other leg with velocities 14-65 km/s. The loop hasbeen shown to have a close correspondence to the magnetic dipole field line

[en] Velocities of some details of monochromatic corona on July 31, 1981, were measured in the sky plane at the west limb. The ascent of arches and plasmoids clots in the condensations with velocities of about 10 km/s were observed in the green line Fe 14lambda5303. In the red line Fe10lambda6374 the velocities of ascent of two arches were about 11-25 km/s. Each of the investigated details is seen only in one emission line and is absent bout 11-25 km/s. Each of the investi

[en] Using pictures of the monochromatic corona taken in FeXIV 5303 A and FeX 6374 A, spectral lines at two points of the path of totality, differing by one hour in time of observation, motions of some structural details could be detected. (author)