scholarly journals Bright Stars in Five LMC Star Clusters

1986 ◽  
Vol 116 ◽  
pp. 417-418
Author(s):  
E. Kontizas ◽  
E. Xiradaki ◽  
M. Kontizas
Keyword(s):  
Star Clusters ◽  
Spectral Classification ◽  
Schmidt Telescope ◽  
Binocular Microscope ◽  
Objective Prism ◽  
Low Dispersion

The bright stars of five LMC clusters were classified for deriving the distribution of various spectral types. The studied clusters are very young (NGC 2093) young (NGC 1818, NGC 2157) intermediate (NGC 1831) and old (NGC 1806) (Van den Bergh 1981). The spectral classification of the stars was carried out using film copies of the 1.2 m Schmidt telescope objective prism plates. Medium dispersion (830 Å at Hγ) unwidened YJ and widened UJ and low dispersion (2440 Å at Hγ) UJ were examined by means of a binocular microscope. Details of the criteria used for the classification are described by Kontizas et al (1985).

scholarly journals Bright Stars in the SMC Clusters

1986 ◽  
Vol 116 ◽  
pp. 405-406
Author(s):  
E. Kontizas ◽  
A. Dapergolas ◽  
M. Kontizas
Keyword(s):  
Short Exposure ◽  
Schmidt Telescope ◽  
Circular Area ◽  
Magnitude Range ◽  
Cluster Area ◽  
Binocular Microscope ◽  
Objective Prism ◽  
Low Dispersion ◽  
Parent Galaxy

The bright stars for 15 SMC clusters were classified in order to derive the distribution of various spectral types. The studied clusters represent all evolutionary ages (disk, intermediate and halo) and are located at various places of the parent galaxy. The spectal classification of the stars was carried out using film copies of the 1.2 m Schmidt telescope objective prism plates. Low dispersion (2440 Å at Hγ) and medium dispersion (830 Å at Hγ) unwidewed UJ and RI spectra were examined by means of a binocular microscope. Short exposure plates were used as well for the most bright stars and particularly for the stars at the central areas where crowding is more severe. More details about the used material and the criteria used for the classification are described by Kontizas et al (1985). For each cluster a circular area was examined inside its tidal radius. (Kontizas, 1984). The stars in the innermost part of the populous clusters were not classified because of the overlapped images. Stars of fields in the vicinity of each cluster were also classified to find the contribution of field stars in the cluster area. The magnitude range of the studied stars is 14.5<V<17.50.

scholarly journals Contributions and Prospects for Spectral Classification of Stars with Objective Prism Techniques

1979 ◽  
Vol 47 ◽  
pp. 127-136
Author(s):  
E. K. Kharadze
Keyword(s):  
Galactic Structure ◽  
Spectral Classification ◽  
Missing Mass ◽  
Mass Problem ◽  
Important Stage ◽  
Objective Prism ◽  
Low Dispersion

The following topics will be discussed: a) A few historical comments; b) MK classification - the most important stage of classification work; c) Recently revealed peculiarity features and the problem of further differentiation of the classification scale; d) Classification work in the USSR; e) The role of classification results with respect to galactic structure studies; f) Low dispersion spectra and faint M-type stars and the missing mass problem; g) Extraterrestrial spectral observations: new promising means for research.

scholarly journals A Test of the Accuracy of low Dispersion Objective Prism: Spectral Classification of Late-Type Stars Using DDO Photometry

1976 ◽  
Vol 72 ◽  
pp. 73-73
Author(s):  
J. J. Clariá ◽  
W. Osborn
Keyword(s):  
Band System ◽  
Class I ◽  
Spectral Features ◽  
Spectral Classification ◽  
Late Type ◽  
Intermediate Band ◽  
Metal Abundance ◽  
Objective Prism ◽  
Low Dispersion

A test has been made of the reliability of the multidimensional classification of late-type stars from low dispersion objective prism plates recently attempted by Stock and Wroblewski. Such classification at low dispersion is difficult due to the problem of separating the effects of luminosity from those of abnormal metal abundance. A sample of the stars classified by Stock and Wroblewski as metal weak (pec) and of those classified as luminous stars (class I) were observed using the DDO intermediate-band system. The photometry shows that the stars classified as pec are indeed population II giants, of low metal abundance ([Fe/H] < −1.0). The stars classified as I, however, were found in general not to be true supergiants but rather a mixture of various types of giants, such as CN strong stars, with spectral features that resemble, in one way or another, those of higher luminosity stars.

scholarly journals Spectral Classification from Low Dispersion Objective Prism spectra taken with the UK 1.2m Schmidt Telescope

1979 ◽  
Vol 47 ◽  
pp. 259-270
Author(s):  
K. Nandy
Keyword(s):  
Red Shift ◽  
Spectral Classification ◽  
Schmidt Telescope ◽  
Objective Prism ◽  
Measuring Machine ◽  
The Uk ◽  
Low Dispersion

AbstractA thin prism (with a dispersion of 2480 Å/mm at Hγ and Hβ) is now available for the UK 1.2m Schmidt telescope. Å 60-min. unwidened exposure on a Ilia-J (hypersensitized) emulsion reaches fainter than 20 mag. The spectra are measured and digitised with the fast measuring machine COSMOS. A method to determine the red shift of faint galaxies and the spectral classes of faint stars and galaxies from the digitised spectra will be described.

scholarly journals Automatic extraction and classification of low-dispersion objective prism stellar spectra

2000 ◽  
Vol 142 (2) ◽  
pp. 339-345 ◽  
Author(s):  
E. Bratsolis ◽  
I. Bellas-Velidis ◽  
A. Dapergolas ◽  
E. Kontizas ◽  
M. Kontizas
Keyword(s):  
Automatic Extraction ◽  
Stellar Spectra ◽  
Objective Prism ◽  
Low Dispersion

scholarly journals Preliminary Investigation of Quantitative Spectral Classification by Means of Objective-Prism Spectra Obtained with the Broerfelde Schmidt Telescope

1973 ◽  
Vol 50 ◽  
pp. 134-137
Author(s):  
J. V. Clausen
Keyword(s):  
Preliminary Investigation ◽  
Spectral Classification ◽  
Schmidt Telescope ◽  
Mean Error ◽  
Objective Prism ◽  
Hydrogen Lines

Different methods, used for measuring the strength of hydrogen lines in objective-prism spectra, are discussed and the parameters are compared with the photoelectric β-index. It is found that for A5V–G1V stars β can be given with a mean error of ±0.m020 (one spectrum).

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