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 Automatic Extraction and Classification of Low-Dispersion Objective-Prism Stellar Spectra

2000 ◽  
Vol 9 (4) ◽  
Author(s):  
E. Bratsolis ◽  
F. Maragoudaki ◽  
I. Bellas-Velidis ◽  
A. Dapergolas ◽  
E. Kontizas ◽  
...  
Keyword(s):  
Automatic Extraction ◽  
Stellar Spectra ◽  
Objective Prism ◽  
Low Dispersion

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.

Automated detection and classification of objective prism stellar spectra

1999 ◽  
Vol 18 (3) ◽  
pp. 413-424
Author(s):  
I. Bellas-Velidis ◽  
F. Pasian ◽  
E. Kontizas ◽  
A. Dapergolas ◽  
E. Bratsolis ◽  
...  
Keyword(s):  
Automated Detection ◽  
Stellar Spectra ◽  
Objective Prism

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 A survey programme for QSO and related objects

1978 ◽  
Vol 79 ◽  
pp. 303-304
Author(s):  
H. Lorenz
Keyword(s):  
Quantitative Evaluation ◽  
High Redshift ◽  
First Results ◽  
Objective Prism ◽  
Reliable Classification ◽  
Low Dispersion

I would like to give the first results of a survey programme for high redshift quasars and related objects on the Tautenburg-Schmidt plates. It is known that objective prism plates are very useful for detecting these objects. the smaller the dispersion of the spectra, the fainter are the objects that can be found. Our Schmidt correcting lens gives spectra with the dispersion of 2500 Å mm−1 at Hγ. the limiting magnitude is about 19m in the B range. At this very low dispersion reliable classification of the objects requires the extraction of all the information stored on the plate. That means that a quantitative evaluation should supplement visual insepction.

scholarly journals Recent Developments in the Work on Automated Spectral Classification by Means of Objective Prism Spectra

1994 ◽  
Vol 161 ◽  
pp. 253-254
Author(s):  
V. Malyuto ◽  
T. Shvelidze
Keyword(s):  
Spectral Classification ◽  
Proper Motions ◽  
Stellar Spectra ◽  
Meridional Section ◽  
Spectrometric Data ◽  
Software Packages ◽  
The Galaxy ◽  
Recent Developments ◽  
Objective Prism

Some years ago a complex programme of studying the main meridional section of the Galaxy was started by astronomers of Kiev, Tartu, Abastumani and Vilnius Observatories with the aim of improving our knowledge of spatial and kinematic characteristics of stellar populations. Characteristic to the programme is the use of absolute proper motions of stars together with automated quantitative spectral classification for large stellar-statistical samples. The data are gathered in areas lying within 30° of the main meridional section of the Galaxy. To classify stars, objective prism stellar spectra of intermediate dispersion (166 å/mm at Hγ), obtained with the 70 cm meniscus telescope at the Abastumani Astrophysical Observatory, are used. The field diameter is 4° 50′, and the limiting photographical stellar magnitude is about 12 m . Our system of automated quantitative spectral classification of F-K stars applies criteria evaluation and is mainly based on two software packages: the SDR package for spectrometric data reduction and the CTATEC-2 package determining the linear regression model used for classification (Malyuto &amp; Shvelidze 1989; Malyuto, Pelt &amp; Shvelidze 1993).

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.

Sign in / Sign up

Export Citation Format

Share Document