Galactic and Extragalactic Studies: III. Photographs of Thirty Southern Nebulae and Clusters.
Galactic and Extragalactic Studies: III. Photographs of Thirty Southern Nebulae and Clusters.
复制标题
银河系和河外研究：III。
DOI：
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发表时间：
1940
影响因子：
11.1
通讯作者：
J. Paraskevopoulos
中科院分区：
文献类型：
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作者：
H. Shapley;J. Paraskevopoulos
大约四分之三的外部星系足够接近接近分类是螺旋星系，大多数螺旋星系可以很容易地放在六个常见的类别中。类似地，球状星系也很容易被归类为几个亚型，它们之间很少有异常。然而，这些不寻常的形式，无论是像麦哲伦云那样混乱不规则的，还是仅仅是通常类型的螺旋星系和球状星系的特殊变化，都是不寻常的兴趣，也许在星系结构和发展的研究中具有特殊的重要性。下面几页所描绘的星云和星团中包括了几种具有启发性的奇异现象和异常形式。有些已经由哈佛或其他天文台发表，但其中大多数是第一次在这里提出。除了图2中的复制品外，所有照片都是在布隆方丹的博伊登站用60英寸反射镜拍摄的。比例尺为26英寸到毫米。通常我们使用Cramer高速乳剂，用rodinal显影。复制的照片是从正常的星团和星云研究过程中制作的底片中挑选出来的;没有特别费心去获得特别适合出版的照片。像往常一样，更精细的细节在复制中丢失了，但仍然足以表明其中一些物体的特殊重要性以及进一步研究的可行性，光度学和光谱学。在所有图中，北在顶部，西在右侧，除了图1，西在顶部，南在右侧。31
Approximately three-fourths of the external galaxies that are near enough for close classification are spirals, and most of the spirals can be easily placed in half a dozen common categories. Similarly the spheroidal galaxies are readily assigned to a few subtypes, rarely with abnormalities among them. The unusual forms, whether chaotically irregular like the Magellanic Clouds, or merely peculiar variations on the usual types of spiral and spheroidal galaxy, are, however, of uncommon interest and perhaps of special importance in the study of galactic structures and development. Several instructive curiosities and abnormal forms are included among the nebulae and clusters represented on the following pages. Some have already been published by Harvard, or by other observatories, but most of them are here presented for the first time. With the exception of the reproduction in figure 2, all photographs were made with the 60-inch reflector at the Boyden Station, Bloemfontein. The scale is 26" to the millimeter. Generally we have used Cramer High Speed emulsions, developing with rodinal. The reproduced photographs are selected from plates made in the regular course of work on clusters and nebulae; no particular pains were taken to obtain photographs specially suited to publication. As usual, the finer details are lost in the reproduction, but enough remains to indicate the peculiar importance of some of these objects and the advisability of further study, photometric and spectroscopic. In all figures North is at the top, West on the right, except for figure 1 for which West is at the top and South on the right. 31