scholarly journals A Set of Grisms for FORS

1995 ◽  
Vol 149 ◽  
pp. 27-28 ◽  
Author(s):  
W. Fürtig ◽  
W. Seifert
Keyword(s):  
Wavelength Range ◽  
Field Of View ◽  
Parallel Beam ◽  
First Order ◽  
Large Telescopes ◽  
The University ◽  
Low Dispersion

The University Observatories of München and Göttingen and the Landessternwarte Heidelberg are building in cooperation with ESO two almost identical FOcal Reducer /low-dispersion Spectrographs (FORS) for the ESO Very Large Telescopes. FORS allows low-dispersion multiobject spectroscopy (19 slits) and longslit spectroscopy in the wavelength range of 330 to 1100 nm. A set of standard grisms with reciprocal dispersions of 45 ...230 Å/mm working in the first order are foreseen. With a slitwidth of 1 arcsec the resulting spectral resolutions range from 180 to 1800.For further FORS details see Appenzeller and Rupprecht (1992) and Seifert et al. (1994).The standard grisms are located in a grism wheel in the parallel beam between the collimator and the camera. Seven of eight positions are available for grisms. The free diameter of the grisms is 135 mm to cover the whole field of view of FORS. To avoid reflection ghosts the entrance surfaces are all tilted by .

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 Estimation of Tadalafil Using Derivative Spectrophotometry in Bulk Material and in Pharmaceutical Formulation

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Zamir G. Khan ◽  
Amod S. Patil ◽  
Atul A. Shirkhedkar
Keyword(s):  
Wavelength Range ◽  
Area Under Curve ◽  
Pharmaceutical Formulation ◽  
Second Order ◽  
Order Derivative ◽  
Uv Spectrophotometry ◽  
First Order ◽  
Beer's Law ◽  
Beer’S Law ◽  
Derivative Uv Spectrophotometry

Four simple, rapid, accurate, precise, reliable, and economical UV-spectrophotometric methods have been proposed for the determination of tadalafil in bulk and in pharmaceutical formulation. “Method A” is first order derivative UV spectrophotometry using amplitude, “method B” is first order derivative UV spectrophotometry using area under curve technique, “method C” is second order derivative UV spectrophotometry using amplitude, and “method D” is second order derivative UV spectrophotometry using area under curve technique. The developed methods have shown best results in terms of linearity, accuracy, precision, and LOD and LOQ for bulk drug and marketed formulation as well. In N,N-dimethylformamide, tadalafil showed maximum absorbance at 284 nm. For “method A” amplitude was recorded at 297 nm while for “method B” area under curve was integrated in the wavelength range of 290.60–304.40 nm. For “method C” amplitude was measured at 284 nm while for “method D” area under curve was selected in the wavelength range of 280.80–286.20 nm. For methods A and B, tadalafil obeyed Lambert-Beer’s law in the range of 05–50 μg/mL while for “methods C and D”, tadalafil obeyed Lambert-Beer’s law in the range of 20–70 μg/mL, and-for “methods A, B, C, and D” the correlation coefficients were found to be > than 0.999.

Interpretation of Electron Transfer Spectra of Iridium (IV) and Osmium(IV) Mixed Chloro-Bromo Complexes

1967 ◽  
Vol 22 (6) ◽  
pp. 945-954 ◽  
Author(s):  
Chr. Klixbüll Jørgensen ◽  
W. Preetz
Keyword(s):  
Electron Transfer ◽  
Faraday Effect ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
University Of Virginia ◽  
First Order ◽  
Order Of Magnitude ◽  
Moderate Difference ◽  
The University ◽  
As If

The previous M.O. treatment of unsubstituted hexahalides has been modified, taking the results on Faraday effect obtained at the University of Virginia into account. The absorption spectra previously measured of the complexes (M=Os, Ir) trans-MCl4Br2— and trans-MCl2 Br4— are interpreted by a M.O. treatment for the symmetry D4h as electron transfer transitions, including a first-order relativistic (spin-orbit coupling) correction. The concept of holohedrized symmetry is sufficiently valid to allow a description of MCl5Br— and MClBr5— as if they were tetragonal with centre of inversion and ƒac-(or cis-)MCl3Br3— as if they were cubic. It is shown that the ligand-ligand antibonding effects have the same order of magnitude as the moderate difference in optical electronegativity between Cl- and Br-.

scholarly journals The periodogram and its optical analogy

1906 ◽  
Vol 77 (515) ◽  
pp. 136-140 ◽  
Keyword(s):  
Parallel Beam ◽  
First Order ◽  
Reflected Light ◽  
Original Definition ◽  
Optical Analogy

I have recently applied the periodogram method to the investigation of several fluctuating quantities, and the experience thus gained has led me to modify slightly the original definition. Having always laid stress on the fact that the periodogram supplies by calculation the transformation which the spectroscope instrumentally impresses on a luminous disturbance, I may now enter a little more closely into this optical analogy, and thus lead up to what I hope will be the final definition. Consider a parallel beam of light falling on a grating, the reflected light being collected at the focus of an observing telescope in the usual way. For simplicity of calculation I assume that the grating considered is of a particular type, which, in a former paper, I have called a simple grating. Such a grating only gives two spectra of the first order.

scholarly journals A High-Velocity Component of Atomic Hydrogen in Comet Bennett (1970 II)

1976 ◽  
Vol 25 (Part1) ◽  
pp. 316-321
Author(s):  
H. U. Keller ◽  
Gary E. Thomas
Keyword(s):  
Radiation Pressure ◽  
Velocity Component ◽  
Atomic Hydrogen ◽  
Orbital Plane ◽  
Field Of View ◽  
Lyman Alpha ◽  
Hydrogen Density ◽  
University Of Colorado ◽  
Alpha Emission ◽  
The University

The Lyman alpha emission from Comet Bennett (1970II) was measured near perihelion (March 1970) by the University of Colorado ultraviolet photometer experiment on OGO-5 The spectrometer field of view of about 3° crossed the cometary hydrogen coma four times. The hydrogen coma was observed to extend more than 30 x 106 km in the antisolar direction.A model for the hydrogen density was developed which took the actual cometary motion and the gradients of the forces of gravitation and radiation pressure into account Exact trajectories of atoms in the orbital plane representing the column densities perpendicular to the plane were calculated. The variation of the hydrogen lifetime along the trajectory as well as the solar Lα profile were considered.

scholarly journals A Spectropolarimetric Atlas of 61 Bright Northern Be Stars

2000 ◽  
Vol 175 ◽  
pp. 48-50 ◽  
Author(s):  
Karen S. Bjorkman ◽  
Marilyn R. Meade ◽  
Brian L. Babler
Keyword(s):  
Wavelength Range ◽  
Spectral Resolution ◽  
Wavelength Dependence ◽  
Be Stars ◽  
University Of Wisconsin ◽  
Time Period ◽  
Ccd Detector ◽  
Ccd Observations ◽  
Full Analysis ◽  
The University

AbstractWe are developing an atlas of spectropolarimetric observations of 61 bright northern Be stars obtained from 1989-94 using the halfwave polarimeter (HPOL) at the 0.9m telescope of the University of Wisconsin Pine Bluff Observatory (PBO). The data cover the wavelength range from about 3400-7600Å, with a spectral resolution of about 25Å. This atlas will contain all data (297 observations total) obtained as part of a survey program with HPOL during the time when the detector in use was a dual Reticon array; the survey observations with HPOL continue, using a new CCD detector which extends the spectral coverage out to 1.05μm and improves the spectral resolution to about 12Å. The CCD observations will be presented later in a second volume of the atlas.Only a brief summary of the findings of the survey from the first 5 years of the project is presented here. A full analysis of the data will be included in a paper to be published elsewhere. The general wavelength dependence of polarization for classical Be stars can be considered on the basis of these observations, and results on polarimetric variability are available. In particular, we find that 56% (20 of 36) of the Be stars observed 3 or more times from 1989-94 show significantly variable polarization at the level of 0.1% changes (inclusion of preliminary results from the continuing CCD survey indicates that the percentage is even higher). The timescales for these changes range from as short as night-to-night to as long as several months. Several of the stars showed evidence for polarimetric “outbursts” during the time period covered by the observations.

scholarly journals Spectroscopic and Polarimetric Observations of AC Her and UU Her

1989 ◽  
Vol 106 ◽  
pp. 296-296
Author(s):  
M.A. Nook ◽  
J.A. Cardelli ◽  
K.H. Nordsieck
Keyword(s):  
Wavelength Range ◽  
Spectral Resolution ◽  
Preliminary Results ◽  
Cassegrain Telescope ◽  
The University

We present preliminary results obtained between March and August of 1987 of a two-year spectropolarimetric study of 10 RV Tauri stars. The observations were made at the University of Wisconsin's Pine Bluff Observatory using the 36 inch cassegrain telescope with a Lyot polarimeter. The spectral resolution of the instrument was 6 A and covered the range between 4350 A and 7500 A. The polarimetry covered the same wavelength range but is binned in four broad bands at 4828 A, 5361 A, 6025 A, and 6877 A.

Theoretical study of a W-fiber with a central dip yielding low dispersion over a wide wavelength range

1989 ◽  
Vol 74 (1-2) ◽  
pp. 49-53 ◽  
Author(s):  
K.V.S. Subramaniyam ◽  
V.J. Menon ◽  
P. Khastgir ◽  
K.K. Dey
Keyword(s):  
Wavelength Range ◽  
Theoretical Study ◽  
Wide Wavelength Range ◽  
Low Dispersion

scholarly journals Dispersion of Interstellar Polarization

1965 ◽  
Vol 7 ◽  
pp. 57-64
Author(s):  
Thomas Gehrels
Keyword(s):  
Data Processing ◽  
High Altitude ◽  
Wavelength Range ◽  
Wavelength Dependence ◽  
Probable Error ◽  
Percentage Polarization ◽  
University Of Arizona ◽  
The University ◽  
Observing Techniques

The Wavelength Dependence of Polarization as observed in 32 stars, for which the Henry Draper numbers are given, is shown in figure 1. Details of some of these observations are presented in reference 1.The equipment is now being used with the new 154-cm Catalina reflector of the Lunar and Planetary Laboratory at the University of Arizona. The instrumental polarizations are nearly zero. The data processing and observing techniques have been further improved; the precision is mainly determined by statistics such that the internal probable error in the percentage polarization is ±0.03 percent (±0.0006 magnitude) for a half-hour observation per filter on objects brighter than about 7 magnitudes. The wavelength λ ranges from 0.33 to 0.95 μ covered by seven filters of bandwidth of about 0.05 μ. The wavelength range is being extended to 1.2, 1.6, and 2.2 μ and, with high-altitude ballooning, to 0.28 and 0.22 μ.

Use of Laser in Precision Leveling

1972 ◽  
Vol 26 (4) ◽  
pp. 369-383 ◽  
Author(s):  
Adam Chrzanowski ◽  
Hans-Dirk Janssen
Keyword(s):  
New Brunswick ◽  
Turbulent Atmosphere ◽  
Laser Level ◽  
First Order ◽  
The University ◽  
New Instruments

Three new instruments for precision leveling have been developed at the University of New Brunswick: the Photoelectric Laser Level; the Laser/Ni-007, a combination of He-Ne laser with the Zeiss-Jena Ni-007 geodetic level; a Self-Aligning Centering Detector for laser leveling with long sights in a turbulent atmosphere. The instruments have been laboratory and field tested in a differential geodetic leveling and in leveling across rivers. First-order geodetic accuracy has been obtained.

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