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Article
The structure of the dense cores of Hii regions
The latest observational and theoretical evidence which suggests the existence of a large number of partially ionized globules (PIG's) in the cores of Hii regions is presented.
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Article
A reappraisal of several extensive phenomena of the high galactic latitudes
This is the first of two papers dealing with the extensive high latitude phenomena. The relationships between the diffuse and filamentary gaseous nebulosity, the giant radio loops and the high, medium and low ...
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Article
A two-beam, multi-mode, nebular-stellar photometer
The design, construction and use of a multi-purpose photometer is discussed. It is intended to work between 9000 Å to 3700 Å on the 25-inch Turner-Newall refractor of the Athens National Observatory and eventu...
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Article
Observations of the general background Hα emission from the galactic plane
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Article
Observations of high velocities inHii regions with a two-etalon Fabry-Pérot spectrometer
High internal motions of the ionized material in theHii regions M 8, M16, M 17 and the Orion Nebula were searched for with a two-etalon Fabry-Perot monochromotor. The profiles of the [Oiii], 5007 Å and in one cas...
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Article
The variations of the electron density throughout the Orion Nebula
New measurements are reported of the [OII] brightness ratio across the Orion Nebula. These are compared to all previous measurements of this ratio. The variations of the local electron density throughout the v...
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Article
Further observations of the filamentary nebulosity around the cetus Arc (Loop 2)
Previously some filamentary nebulosity was discovered around the outer edge of the Cetus Arc (Loop 2). Some further observations have now been made of this. To determine an upper limit to its proper motion it ...
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Article
The variations of the electron density within M8
The ratios of the brightnesses of the [Oii] lines at 3729 Å and 3726 Å were measured at 37 positions across M8. A multiple shell model was then constructed to estimate the large-scale variations of this ratio wit...
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Article
Scanning Fabry-Pérot interferometers for nebular studies
The reasons for applying scanning Fabry-Pérot interferometers to the study of faint but extensive gaseous nebulae are outlined. Three ways of increasing the luminosity-resolutin product of the Fabry-Pérot are ...
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Article
An investigation of a peculiar nebula in monoceros
A faint nebula, between the Rosette and NGC 2264, appears to be a supernova remnant. This was photographed with long exposures through narrow filters centred on the bright nebular emission lines. Interferogram...
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Article
Filter and interferometer observations of twoHii regions
The Rosette Nebula was photographed through filters isolating the Hα,OII andOIII nebular emission lines. Isophotes were constructed at these wavelengths. Measurements of the radial velocity differences across the...
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Article
Cameras and filters for nebular photography
The parameters of filter-cameras for nebular photography are outlined and a method of using confocal paraboloids to give the basic camera a higher resolution is investigated. Some astronomical problems requiri...
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Article
An astronomical Fabry-Pérot interferometer
A description is given of an improved version of Flynn's photo-electric, pressure-scanning, Fabry-Pérot (F.-P.) interferometer which has been built for the purpose of studying line emission from diffuse gaseou...