Our Astronomical Column

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    Abstract

    PHOTOGRAPHIC NEBULOSITIES IN THE MILKY WAY.— In the March number of Astronomy and Astro-Physics, and in several recent numbers of Knowledge, Prof. E. E. Barnard describes a number of wisps of nebulosity and diffused masses of luminous haze discovered upon photographs taken by him with a portrait lens six inches in aperture and having a focal length of thirty-one inches. A remarkable and large nebulous mass, situated about R.A. 21h. 34m. Decl. + 56° 50′ appeared upon a plate exposed for seven hours. The picture shows a straggling group of bright stars in the centre of the nebula, which is more than two degrees in diameter. The group of stars is visible to the naked eye as a hazy spot, about three degrees north-west of the variable μ Cephei, the brightest star in the group being D.M. + 56° 2617. The star D.M. + 57° 2309 (mag. 6.5) is also shown by the photograph to be surrounded by a rather unsymmetrical dense circular nebulosity. This object was not previously known to be nebulous, though Prof. Barnard says that with the telescope the nebulosity can be seen as a hazy glow about the star. The region of the Milky Way lying north and east of Orion appears to be singularly rich in large diffused nebulosities. Photographs show that ω Orionis and λ Orionis are nebulous, while there is a faint and large diffused glow near the stars v and ξ Orionis. There was a suspicion of a large nebulosity about α Orionis on one of the plates, but this has not yet been verified. The existence of the other nebulosities, however, has been established either by telescopic observation or new photographs. A photograph obtained at the beginning of last month shows two very singular fan-shaped patches of nebulosity close to γ Cassiopeiæ. These are about 15′ in diameter and point towards the star. They could just be seen by Prof. Barnard with the 12-inch of the Lick Observatory, but he thinks they would never have been detected if the photographic plate had not revealed them. Photographs of the region about 15 Monoceros show that this group of bright stars is mixed up with misty matter having a diameter of about three degrees. The place of 15 Monoceros for 1860 is R.A. 6h. 33m. 16s. Decl. + 10° 1′.3, and the condensation of the remarkable nebula in question is 12′ south preceding the star. Prof. Barnard has now photographed the Milky Way from Scorpio to Orion, discovering many masses of nebulosity on the way. His pictures are not only beautiful views, but valuable records of the structure of the different regions portrayed.

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