Morphological and evolutional features of Ellerman bombs were studied with He filtergrams of two active regions very close to the solar limb. We quantitatively determined the elongated or spike-like shape of the bomb. The mean apparent length of 174 bombs is 1.1 arc sec, while 80 % of 204 bombs have a diameter of less than 0.6 arc sec. The mean lifetime of 77 bombs is about 12 min at Hc~ -1.2 A. The first maximum brightness of a typical bomb is attained, on average in about 2 min. Bombs grow longer in the first brightening phase and their mean upward velocity explains the blue asymmetry of He emission profiles of moustaches.
The outine of a new solar Flare-Monitoring-Telescope is given, which was built at the Hida Observatory of Faculty of Science, Kyoto University, in the first financial year of the Japan's STEP project. The telescope is unique among currently-operating solar flare-patrol-telescopes, because it can simultaneously observe five solar images, which are four full disc images in Ha center, Ha + 0.8 A, Ha -0.8 A and continuum, and one solar limb image in Ha center. After its start of operation it was confirmed that this telescope system is very useful to study the dynamical features of Ha filament disappearance, because it can, for the first time, continuously record the full solar disc simultaneously in three wavelengths of the Ha line. Two typical examples of Ha filament disappearance observed with the telescope are demonstrated and are comparatively studied. It is found that the more dynamical and more energetic Ha filament eruption causes the larger enhancement of soft X-ray bright arcade structure observed with the Soft X-ray Telscope of Yohkoh.
No abstract
A real-time frame selector (RTFS), a new observational system, was developed at the Domeless Solar Telescope of Hida Observatory, Kyoto University. Our RTFS allows us to automatically select out a video frame with the highest spatial resolution in a series of live video images during a prescribed time span, and stores the selected one in digital format to a hard disk file. We applied the RTFS to observations of solar granulation in the G-band wavelength (λ 4308 Å, passband 20 Å) and obtained a time series of data with a step of 15 seconds. By the method of local-correlation tracking, we derived the horizontal velocity field with the granulation pattern as tracers. In a quiet photosphere, we found the so-called mesogranulation flow field, clearly. Supergranular flow patterns were also detected and identified from a comparison with an Hα wing image. On the other hand, in a sunspot area, we found new evidence of horizontal inflow from penumbral areas to umbral areas as well as the presence of another circumferential inflow from the surrounding photosphere to the penumbral outer edge.
In an active region, several points were observed to brighten progressively on the monochromatic image of Ha -1.2 ~ formed by the Domeless Solar Telescope installed recently at Hida Observatory. The phenomena were interpreted as small flares or subflares. The propagation velocity was measured in two cases and discussed in terms of the multiple loop activation observed in EUV radiation.A new Domeless Solar Telescope has been ready to operate at the beginning of 1980 in Hida Observatory. The principal characteristics of the design of this telescope lies in obtaining geometrical resolution on the solar surface as high as possible. Although the full functions of the telescope and the accessaries were not yet displayed, several kinds of observations were made during the testing period. The details of the telescope and the accessaries will be published elsewhere. We have found progressive brightenings of very short duration in an active region, MacMath region 16867, by the cinematographic observation. The phenomenon seems to be the optical counterpart of the multiple loop activation detected on the EUV observations of Skylab (Vorpahl, 1976;Widing and Dere, 1977). The aim of the present note lies in the description of observations and the brief discussions of the observed propagation velocity.The effective aperture of the Domeless Solar Telescope is 60 cm in diameter and the light beam is fed by a Gregorian system through vacuum tubes into the observing room and thus the solar image of 30 cm in diameter is formed on the slit of the vacuum spectrograph. In the present observation, a flat mirror was inserted into the light beam before the spectrographic slit and the monochromatic solar image was formed on the Nikon motor drive camera after passing through the Zeiss birefringent filter of He line with the passband of 0.25 A. The instant of good seeing was watched so that the time interval between any two consecutive exposures was not uniform. However, the average time interval between exposures was 5 s and the observation started at 22 : 03 : 38 UT and ended at 23 : 22 : 01 UT of 5th July, 1980. After the observation a roll of 16 mm film movie was edited with uniform time lapse by arranging the original 35 mm negatives.All the original monochromatic images were taken in the wing of He line i.e. Ha -1.2 A. Then the complicated structure such as fibrils and threads appeared on the image of Ha-line center is not seen but only the bright points such as moustaches can be followed in the movie: The 1.5 hr of the observation were reduced to about 5 min in the movie. *
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