scholarly journals The PYTHEAS concept and applications

1995 ◽  
Vol 149 ◽  
pp. 300-307
Author(s):  
Y.P. Georgelin ◽  
G. Comte ◽  
E. le Coarer
Keyword(s):  
Spectral Range ◽  
Spectral Resolution ◽  
Flux Measurement ◽  
Microlens Array ◽  
High Spectral Resolution ◽  
Wide Spectral Range ◽  
Field Sampling ◽  
Fabry Perot ◽  
Field Element ◽  
Integral Field

AbstractThe PYTHEAS instrumental concept is an attempt to solve the problem of getting a complete tridimensional coverage of the observed field with a high spectral resolution across a wide spectral range. It is an integral field spectrometer derived from the TIGER spectrograph (field sampling with a microlens array) in which a scanning Fabry-Perot (FP) is introduced. The spectral resolution is given by the F P and the spectral range is that allowed by the grism of TIGER. The information is recorded on the CCD as a set of channeled spectra, for each microlens and each scanning step of the FP. The spectrum of each sampled field element is reconstructed from flux measurement of the Fabry spots defining the channeled spectra.The application ranges of this instrument are reviewed with emphasis on the potential interest in globular cluster studies.

scholarly journals Study of a High Spectral Resolution Hyperspectral LiDAR in Vegetation Red Edge Parameters Extraction

2019 ◽  
Vol 11 (17) ◽  
pp. 2007 ◽  
Author(s):  
Changhui Jiang ◽  
Yuwei Chen ◽  
Haohao Wu ◽  
Wei Li ◽  
Hui Zhou ◽  
...  
Keyword(s):  
Spectral Range ◽  
Spectral Resolution ◽  
Spatial Information ◽  
Research Direction ◽  
Parameter Extraction ◽  
Tunable Filter ◽  
High Spectral Resolution ◽  
Red Edge ◽  
Parameters Extraction ◽  
Vegetation Parameter

Non-contact and active vegetation or plant parameters extraction using hyperspectral information is a prospective research direction among the remote sensing community. Hyperspectral LiDAR (HSL) is an instrument capable of acquiring spectral and spatial information actively, which could mitigate the environmental illumination influence on the spectral information collection. However, HSL usually has limited spectral resolution and coverage, which is vital for vegetation parameter extraction. In this paper, to broaden the HSL spectral range and increase the spectral resolution, an Acousto-optical Tunable Filter based Hyperspectral LiDAR (AOTF-HSL) with 10 nm spectral resolution, consecutively covering from 500–1000 nm, was designed. The AOTF-HSL was employed and evaluated for vegetation parameters extraction. “Red Edge” parameters of four different plants with green and yellow leaves were extracted in the lab experiments for evaluating the HSL vegetation parameter extraction capacity. The experiments were composed of two parts. Firstly, the first-order derivative of the spectral reflectance was employed to extract the “Red Edge” position (REP), “Red Edge” slope (RES) and “Red Edge” area (REA) of these green and yellow leaves. The results were compared with the referenced value from a standard SVC© HR-1024 spectrometer for validation. Green leaf parameter differences between HSL and SVC results were minor, which supported that notion the HSL was practical for extracting the employed parameter as an active method. Secondly, another two different REP extraction methods, Linear Four-point Interpolation technology (LFPIT) and Linear Extrapolation technology (LET), were utilized for further evaluation of using the AOTF-HSL spectral profile to determine the REP value. The differences between the plant green leaves’ REP results extracted using the three methods were all below 10%, and the some of them were below 1%, which further demonstrated that the spectral data collected from HSL with this spectral range and resolution settings was applicable for “Red Edge” parameters extraction.

scholarly journals Quantitative spectral classification of Galactic O stars

2018 ◽  
Vol 616 ◽  
pp. A135 ◽  
Author(s):  
F. Martins
Keyword(s):  
Spectral Range ◽  
Spectral Resolution ◽  
Equivalent Width ◽  
Classification Criteria ◽  
High Spectral Resolution ◽  
Spectral Classification ◽  
Class V ◽  
Luminosity Class ◽  
Spectral Class

Our goal is to provide a quantification of several spectral classification criteria for O stars. We collect high-spectral resolution spectra of 105 Galactic O-type stars from various archives. We measured equivalent widths of classification lines. We defined average values of classification criteria for given spectral types and luminosity classes. We find that the ratio He I 4471 to He II 4542 well matches the published ratios for spectral types. We have quantified equivalent width ratios of helium and silicon lines among O8–O9.7 stars to refine spectral class typing in this spectral range. We present quantitative criteria to separate between luminosity class V, IV–III–II (grouped), and I among O3–O8.5 stars, mainly based on the strength of He II 4686. We find that these criteria also define very well the f, (f), and ((f)) classes for O3–O7.5 stars. Among O9–O9.7 stars we quantify the ratios of He II 4686 to He I 4713 and Si IV 4089 to He I 4026 for all luminosity classes. The tabulated values of the classification criteria should help classify any new O-type stars. The final step of the classification process should rely on a direct comparison to standard stars of the assigned spectral type or luminosity class.

scholarly journals High spectral resolution interferometric planetary observations in the 7–25 μ region

1971 ◽  
Vol 40 ◽  
pp. 44-47
Author(s):  
R. A. Hanel ◽  
V. G. Kunde ◽  
T. Meilleur ◽  
G. Stambach
Keyword(s):  
Spectral Range ◽  
Spectral Resolution ◽  
Thermal Emission ◽  
Emission Spectra ◽  
Rotational Structure ◽  
High Spectral Resolution ◽  
The Moon ◽  
Broad Absorption ◽  
Ratio Spectrum ◽  
Venusian Atmosphere

The thermal emission spectra of Venus, Mars, Jupiter, and the moon were observed at the coude focus of the McDonald Observatory 107-inch telescope in the 400–1400 cm−1 spectral range with spectral resolutions of 0.3–0.7 cm−1. A preliminary interpretation of the Venus/lunar ratio spectrum allows identification of four upper state CO2 bands in the Venusian atmosphere at 791, 828, 865, and 961 cm−1 and confirms previous observations of the broad absorption-like depression around 890 cm−1. The rotational structure of the 791 and 961 cm−1 bands is well developed at this spectral resolution.

scholarly journals The Structure and Kinematics of the Ionized Gas In Centaurus A

1987 ◽  
Vol 127 ◽  
pp. 417-418
Author(s):  
J. Bland ◽  
K. Taylor ◽  
P. D. Atherton
Keyword(s):  
Spatial Resolution ◽  
Spectral Resolution ◽  
High Spectral Resolution ◽  
Line Of Sight ◽  
Rotating Disc ◽  
Ionized Gas ◽  
Dust Lane ◽  
Data Cubes ◽  
Fabry Perot ◽  
Centaurus A

The TAURUS Imaging Fabry-Perot System (Taylor & Atherton 1980) has been used with the IPCS at the AAT to observe the ionized gas within NGC 5128 (Cen A) at [NII]λ6548 and Hα. Seven independent (x, y,λ) data cubes were obtained along the dust lane at high spectral resolution (30 km/s FWHM) and at a spatial resolution limited by the seeing (~1″). From these data, maps of the kinematics and intensities of the ionized gas were derived over a 420″ by 300″ region. The maps are the most complete to date for this object comprising 17500 and 5300 fitted spectra in Ha and [NII]λ6548 respectively. The dust lane system is found to be well understood in terms of a differentially rotating disc of gas and dust which is warped both along and perpendicular to the line-of-sight.

A high-spectral resolution tandem Fabry-Perot spectrometer for 17-micrometer wavelength

2006 ◽  
Author(s):  
Takahiro Nagayama ◽  
Tetsuya Nagata ◽  
Takahiro Zenno ◽  
Chie Nagashima ◽  
Mikio Kurita ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
High Spectral Resolution ◽  
Fabry Perot

Development of a high spectral resolution lidar based on confocal Fabry–Perot spectral filters

2012 ◽  
Vol 51 (25) ◽  
pp. 6233 ◽  
Author(s):  
David S. Hoffman ◽  
Kevin S. Repasky ◽  
John A. Reagan ◽  
John L. Carlsten
Keyword(s):  
Spectral Resolution ◽  
High Spectral Resolution ◽  
Spectral Filters ◽  
Fabry Perot ◽  
High Spectral Resolution Lidar

scholarly journals H2 2.12 μm Spectroscopy and Imaging of HH Objects

1989 ◽  
Vol 120 ◽  
pp. 302-302
Author(s):  
H. Zinnecker ◽  
R. Mundt ◽  
A. Moneti ◽  
T.R. Geballe ◽  
W.J. Zealey
Keyword(s):  
Spectral Resolution ◽  
High Spatial Resolution ◽  
Preliminary Test ◽  
High Spectral Resolution ◽  
Line Of Sight ◽  
Line Profiles ◽  
Ir Camera ◽  
Fabry Perot ◽  
Hh Objects ◽  
Hh Object

We have obtained high spectral resolution observations of a number of Herbig-Haro (HH) objects in the H2 v=1-0 S(1) line at 2.12μm. Objects observed included HH1/2, HH7-11, HH19, HH32A, HH40, and HH43, all associated with jet-like features or collimated optical outflows. Here we present velocity-resolved 2.12μm spectroscopy for HH40 (an HH-objects moving close to the line of sight) an for HH43B (an HH-object moving close to the plane of the sky). The full set of observations including interpretation is given in Zinnecker et al. (1989). We also present high spatial resolution H2 2.12μm images of HH40 and HH43. The 2.12μm H2 line profiles were obtained with the UKIRT infrared Fabry-Perot system (effective resolution 30-35 km/s) using a diaphragm of diameter 11” for both HH40 and HH43. The H2 images were obtained with the IR-array imager at the CTIO 1.5m telescope through a narrowband filter centred on the v=1-0 S(1) line. The IR-camera used had 58x62 pixels and a resolution of 0.9”/pixel. The exposure time was 2x120sec and 5x60sec for HH40 and HH43, respectively. The images are sky subtracted, but not fiat fielded, and should be viewed as preliminary test images.

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