Wide-angle Telescope Research Articles

Ultraviolet spectra of Capella

IN December 1973, during observations from the space observatory Orion 2 on Soyuz 13, three spectrograms of Capella (α Aur, GO III, mv=0.2) were obtained in the wavelength region 2,000–3,000 A. The spectrograms were made by a wide-angle meniscus telescope of the Cassesgrain system, with an aperture diameter of 240 mm, an equivalent focal length of 1,000 mm, and a 4-grade quartz prism objective. The dispersion of the spectrograph was 170, 280 and 550 A mm−1, at wavelengths of 2,000, 2,500 and 3,000 A, respectively.

Objective Transmission Gratings for Large Schmidt Telescopes

Several lamellar gratings of 18-in. aperture, with 300 diffraction elements per inch, have been made for determining stellar spectra with wide angle telescopes. Central orders are missing at lambda4800, and weak at adjacent wavelengths. The two, equal first orders are about l(m) weaker than spectra by a prism or echelette grating. Dispersion is linear. The procedure of manufacture is adaptable to larger size. The wavelength at which the central order is missing can be controlled by varying the lamellae thickness. The lamellae are evaporated strips of quartz of 0.5-micro thickness, covering half the face of the support-a spectacle crown, plane parallel plate of ?-in. thickness. The lamellae were deposited by thermal evaporation.

THE CLUSTERING OF GALAXIES

Inspecti of photographs obtained with wide-angle telescopes sho' that the distribution of galaxies over the sky is distinctly nt miform. The observed dumpiness of the distribution of ga ies is believed to be due to a tendency for galaxies to occur in sters. A cluster of galaxies is usually regarded as a distinct >e of aggregate of matter. It is the purpose of this paper to investigate some aspects of the validity of the concept of a cluster of galaxies as a distinct type of organization intermediate between an individual galaxy and the universe as a whole. In other words, is a cluster of galaxies an indivisible unit or can it be divided into subclusters or even smaller units ? Alternatively one may inquire if clusters of galaxies are the largest aggregates of matter or if they are themselves constituents of still larger organizations. In attempting to answer these questions we find it instructive to consider first the Group, which is presumably a rather typical example of a small cluster of galaxies. It is quite apparent that the members of this group are not distributed at random in space. The most striking example is the Andromeda Nebula with its two companions M 32 and NGC 205. A compact binary system is formed by the Magellanic Clouds. On a somewhat larger scale it is at once apparent that most of the members of the Local Group may be placed in two subgroups. One of these subgroups is formed by the Galaxy and the Magellanic Clouds. The other subgroup consists of NGC 147, NGC 185, NGC 205, M 31, M 32, M 33, and possibly NGC 404 and IC 10. The different orders of subclustering of the brightest Local Group members are shown schematically in Table I. It is well known that the surface distribution of galaxies in the region of the Virgo cluster is quite irregular. Some of this apparent irregularity may be due to a tendency toward subclustering within the Virgo cluster proper. More definite evidence of the existence of small-scale dumpiness in the Virgo cluster

The Clustering of Galaxies.

Inspecti of photographs obtained with wide-angle telescopes sho' that the distribution of galaxies over the sky is distinctly nt miform. The observed dumpiness of the distribution of ga ies is believed to be due to a tendency for galaxies to occur in sters. A cluster of galaxies is usually regarded as a distinct >e of aggregate of matter. It is the purpose of this paper to investigate some aspects of the validity of the concept of a cluster of galaxies as a distinct type of organization intermediate between an individual galaxy and the universe as a whole. In other words, is a cluster of galaxies an indivisible unit or can it be divided into subclusters or even smaller units ? Alternatively one may inquire if clusters of galaxies are the largest aggregates of matter or if they are themselves constituents of still larger organizations. In attempting to answer these questions we find it instructive to consider first the Group, which is presumably a rather typical example of a small cluster of galaxies. It is quite apparent that the members of this group are not distributed at random in space. The most striking example is the Andromeda Nebula with its two companions M 32 and NGC 205. A compact binary system is formed by the Magellanic Clouds. On a somewhat larger scale it is at once apparent that most of the members of the Local Group may be placed in two subgroups. One of these subgroups is formed by the Galaxy and the Magellanic Clouds. The other subgroup consists of NGC 147, NGC 185, NGC 205, M 31, M 32, M 33, and possibly NGC 404 and IC 10. The different orders of subclustering of the brightest Local Group members are shown schematically in Table I. It is well known that the surface distribution of galaxies in the region of the Virgo cluster is quite irregular. Some of this apparent irregularity may be due to a tendency toward subclustering within the Virgo cluster proper. More definite evidence of the existence of small-scale dumpiness in the Virgo cluster

Atmospheric effects and periodicities of the cosmic radiation measured 8m below ground

During 1957, measurements were made of the penetrating component of cosmic radiation at 8m underground (17 mwe) using two small identical wide-angle telescopes. Absorption and decay coefficients were determined for 7 periods at the Budapest location, and solar daily variation was observed for four months. The amplitude and phase observations agreed with analogous values reported by others. (T.R.H.)