scholarly journals A New Objective Prism Catalogue of OB and Supergiant B, A, F and G Stars in the Magellanic Clouds

1979 ◽  
Vol 47 ◽  
pp. 155-157
Author(s):  
A. G. Davis Philip ◽  
N. Sanduleak
Keyword(s):  
Magellanic Clouds ◽  
Schmidt Telescope ◽  
Ob Stars ◽  
Objective Prism ◽  
Hydrogen Lines

The Michigan Curtis Schmidt telescope at Cerro Tololo Inter-American Observatory has been used with the “thin” prism (Blanco 1974) to survey the Large and Small Magellanic Clouds. Four plates, covering approximately 90 square degrees, and three plates, covering approximately 70 square degrees, were taken of the Large and Small Magellanic Clouds respectively. One hour exposures on nitrogen baked, IIIa-J plates were obtained. The limiting magnitude of the plates is V = 16 mag. At the dispersion of 1360 Å/mm OB stars can be recognized by their long uv extension, in which no sign of a Balmer discontinuity can be seen. The supergiants can be recognized by the appearance of a Balmer discontinuity and classified into temperature types by the strength of the hydrogen lines.

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).

scholarly journals Lists of Confirmed Planetary Nebulae in the Magellanic Clouds

1978 ◽  
Vol 76 ◽  
pp. 64-64
Author(s):  
N. Sanduleak ◽  
D.J. MacConnell ◽  
A.G. Davis Philip
Keyword(s):  
Emission Line ◽  
Total Mass ◽  
Planetary Nebulae ◽  
High Sensitivity ◽  
Hii Regions ◽  
Magellanic Clouds ◽  
Schmidt Telescope ◽  
Deep Blue ◽  
Two Systems ◽  
Objective Prism

Very deep, blue and red-sensitive objective-prism plates, taken with the Curtis Schmidt telescope at the Cerro Tololo Inter-American Observatory, were used to survey both Magellanic Clouds for unresolved objects which could be classified as highly probable planetary nebulae. The high sensitivity of the baked Kodak IIIa-J emulsion at 5000 Å made it possible to detect the N1 and N2 lines of [OIII] in fainter objects than previously observed. A number of emission-line stars, compact HII regions, and very-low-excitation objects, formerly considered to be probable or possible planetaries, were recognized and excluded. The final lists contain 27 confirmed planetaries in the SMC and 100 in the LMC, a ratio equivalent to the estimated ratio of total mass in the two systems. As would be expected, most of these objects had been detected in previous objective-prism surveys but some apparently new planetaries were found.

A comparison of the classification systems of luminous stars in the northern Milky Way II and IV, for stars assigned two-dimensional spectral types from objective-prism plates

1966 ◽  
Vol 24 ◽  
pp. 70-73
Author(s):  
C. B. Stephenson
Keyword(s):  
Milky Way ◽  
Classification Systems ◽  
Two Dimensional ◽  
Joint Project ◽  
Ob Stars ◽  
Luminosity Class ◽  
Objective Prism ◽  
The Mean ◽  
The Difference ◽  
Hydrogen Lines

For some years a survey for early-type luminous stars in the northern Milky Way has been underway at the Warner and Swasey Observatory and the Hamburg Observatory, as a joint project by the two institutions (1). With the aid of ultraviolet-transmitting objective prisms (Schott UBK7 glass), it has been possible at both institutions to recognize OB stars at a dispersion of about 600Å/mm. Moreover, the appearance of the Balmer discontinuity at low dispersion affords a valuable aid to two-dimensional classification of stars of late B to late F types (2, 3). These two-dimensional classifications, which are based essentially upon the appearance of the continuum (especially the Balmer discontinuity), the hydrogen lines, the K line, and the G band, are assigned in the MK classification nomenclature since they are well correlated with classifications made by means of the real MK classification criteria. The quality of the correlation depends upon location in the HR diagram, but the random probable error appears to be upward of one MK luminosity class and about a quarter of a full letter division in temperature class, except that luminosity class IV is nowhere well distinguished from class V, and class Iab is not really well distinguished from Ia and Ib.The present Cleveland system of assigning two-dimensional spectral types to stars from ultraviolet-included objective-prism plates tends to assign lower luminosities than those of the LS II (–LS I?) system. This fact alone accounts for certainly most of the difference between the numbers of stars assigned two-dimensional spectral types in LS II and in LS IV. The origin of this systematic difference of over a luminosity class is not well explained, but the difference is hardly alarming. The numbers of OB stars in the two catalogues are quite comparable and this is consistent with the fact that no classification system difference for OB stars is known to exist between these two catalogues.Slit spectrograms so far available support the belief that LS IV agrees better in the mean with the MK system than does LS II, though LS IV may also be slightly overluminous in the mean. There is one factor always tending to confuse the transformation from this objective-prism system to MK spectral types: stars having abnormally strong Balmer discontinuities will usually be included in our catalogues with some kind of MK classification, While those with abnormally weak Balmer discontinuities will more often be excluded or assigned to the OB group. This problem is by no means so serious as to detract significantly from the desirability of making objective-prism surveys that pay special heed to the Balmer discontinuity.

Novae in the Magellanic Clouds

1979 ◽  
Vol 46 ◽  
pp. 96-101
Author(s):  
J.A. Graham
Keyword(s):  
Large Magellanic Cloud ◽  
Magellanic Cloud ◽  
Magellanic Clouds ◽  
University Of Michigan ◽  
The Past ◽  
Spectroscopic Information ◽  
Objective Prism ◽  
The University ◽  
Small Cloud ◽  
Low Dispersion

During the past several years, a systematic search for novae in the Magellanic Clouds has been carried out at Cerro Tololo Inter-American Observatory. The Curtis Schmidt telescope, on loan to CTIO from the University of Michigan is used to obtain plates every two weeks during the observing season. An objective prism is used on the telescope. This provides additional low-dispersion spectroscopic information when a nova is discovered. The plates cover an area of 5°x5°. One plate is sufficient to cover the Small Magellanic Cloud and four are taken of the Large Magellanic Cloud with an overlap so that the central bar is included on each plate. The methods used in the search have been described by Graham and Araya (1971). In the CTIO survey, 8 novae have been discovered in the Large Cloud but none in the Small Cloud. The survey was not carried out in 1974 or 1976. During 1974, one nova was discovered in the Small Cloud by MacConnell and Sanduleak (1974).

scholarly journals Hα emission-line stars in molecular clouds

2019 ◽  
Vol 630 ◽  
pp. A90 ◽  
Author(s):  
Bertil Pettersson ◽  
Bo Reipurth
Keyword(s):  
Molecular Clouds ◽  
Young Stellar Objects ◽  
Be Stars ◽  
Stellar Objects ◽  
Strong Concentration ◽  
Ob Stars ◽  
Star Forming ◽  
Hα Emission ◽  
Objective Prism ◽  
Emission Stars

A deep objective-prism survey for Hα emission stars towards the Canis Major star-forming clouds was performed. A total of 398 Hα emitters were detected, 353 of which are new detections. There is a strong concentration of these Hα emitters towards the molecular clouds surrounding the CMa OB1 association, and it is likely that these stars are young stellar objects recently born in the clouds. An additional population of Hα emitters is scattered all across the region, and probably includes unrelated foreground dMe stars and background Be stars. About 90% of the Hα emitters are detected by WISE, of which 75% was detected with usable photometry. When plotted in a WISE colour–colour diagram it appears that the majority are Class II YSOs. Coordinates and finding charts are provided for all the new stars, and coordinates for all the detections. We searched the Gaia-DR2 catalogue and from 334 Hα emission stars with useful parallaxes, we selected a subset of 98 stars that have parallax errors of less than 20% and nominal distances in the interval 1050 to 1350 pc that surrounds a strong peak at 1185 pc in the distance distribution. Similarly, Gaia distances were obtained for 51 OB-stars located towards Canis Major and selected with the same parallax errors as the Hα stars. We find a median distance for the OB stars of 1182 pc, in excellent correspondence with the distance from the Hα stars. Two known runaway stars are confirmed as members of the association. Finally, two new Herbig-Haro objects are identified.

scholarly journals Automated Quasar Detection

1983 ◽  
Vol 104 ◽  
pp. 31-31
Author(s):  
Roger G. Clowes ◽  
John A. Cooke ◽  
Steven M. Beard
Keyword(s):  
Selection Effects ◽  
Schmidt Telescope ◽  
Royal Observatory ◽  
Objective Prism ◽  
Measuring Machine ◽  
The Uk

The existing spectral searches for quasars have increased the number of quasars known very substantially but have not contributed proportionately to an understanding of the collective properties because of the selection effects. To fully exploit the spectral searches we have developed the technique of automated quasar detection (AQD) using objective-prism plates from the UK Schmidt Telescope, the COSMOS measuring machine at the Royal Observatory Edinburgh, and the STARLINK nodes at Durham and Edinburgh.

scholarly journals Objective-Prism Galaxy Redshifts in Fields Around the South Galactic Pole

1984 ◽  
Vol 78 ◽  
pp. 405-408 ◽  
Author(s):  
Q.A. Parker ◽  
H.T. MacGillivray ◽  
R.J. Dodd ◽  
J.A. Cooke ◽  
S.M. Beard ◽  
...  
Keyword(s):  
Large Scale ◽  
Schmidt Telescope ◽  
The South ◽  
Large Numbers ◽  
Objective Prism ◽  
The Uk

AbstractMeasurements made with the COSMOS machine on deep objectiveprism photographs taken with the UK 1.2m Schmidt Telescope are being used to obtain approximate redshifts (accurate to ~ 0.01 in z) for large numbers of galaxies in fields near the South Galactic Pole. The data are suitable for investigations of the distribution of galaxies, such as the detection of large-scale density enhancements or voids.

scholarly journals On the Astronomical Research With the Torun 60/90 Cm Schmidt Telescope

1984 ◽  
Vol 78 ◽  
pp. 211-214
Author(s):  
A. Woszczyk
Keyword(s):  
Scientific Applications ◽  
Schmidt Telescope ◽  
Sky Survey ◽  
Objective Prism ◽  
Astronomical Research

AbstractThe Torun Schmidt telescope and its scientific applications are described. A special attention is given to the Torun Objective Prism Sky Survey.

scholarly journals Classification Based on 102/Å/mm Objective Prism Spectra

1979 ◽  
Vol 47 ◽  
pp. 479-480
Author(s):  
J.V. Clausen ◽  
K.S. Jensen
Keyword(s):  
Schmidt Telescope ◽  
Objective Prism

Equipped with a 15° F2 objective prism the (45/77/150)cm Schmidt telescope of the Copenhagen university Observatory, Brorfelde yields spectra of 102 A/mm at Hα to a limit of approximately mpg =9.5.

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