scholarly journals The Proposed Columbus Mission: High and Low Resolution Spectroscopy in the 100–2000 Å Spectral Region

1984 ◽  
Vol 86 ◽  
pp. 72-75
Author(s):  
Jeffrey L. Linsky
Keyword(s):  
High Resolution ◽  
Spectral Range ◽  
Spectral Region ◽  
Extreme Ultraviolet ◽  
High Spectral Resolution ◽  
Low Resolution ◽  
Interstellar Gas ◽  
Scientists And Engineers ◽  
Ionization Balance ◽  
Far Ultraviolet

For the past year a Joint Working Group of NASA and ESA scientists and engineers has been defining the scientific objectives and instrument parameters for a proposed satellite to obtain far and extreme ultraviolet spectra of stars, interstellar gas, solar system objects, and galaxies. The project, now called Columbus, incorporates the scientific goals of the previously proposed NASA Far Ultraviolet Spectrograph Explorer (FUSE) and ESA Magellan missions.The prime spectral range of Columbus, 900–1200 Å, cannot be observed by IUE or Space Telescope. In this spectral range Copernicus was able to observe bright stars (mv ≤ 6) with high resolution and the Hopkins Ultraviolet Telescope (HUT) will observe faint sources at low resolution, but Columbus will be the first instrument capable of high spectral resolution observations of faint sources (mv ≈ 17). High resolution spectra in the 900–1200 Å region will permit studies of the Lyman lines of atomic H and D, the molecules H2 and HD, resonance lines of C III and O VI, and other species listed in Table 1. Columbus also is being designed to observe the 1200–2000 Å spectral region at high resolution, permitting measurements of many stages of ionization for the same atom (i.e. N I, II, III, V; C II, III, IV; and S II, III, IV, VI). The broad coverage of ionization states is essential for the analysis of interstellar and stellar plasmas where the ionization balance can be quite complex.

scholarly journals Remote sensing of CO<sub>2</sub> and CH<sub>4</sub> using solar absorption spectrometry with a low resolution spectrometer

2012 ◽  
Vol 5 (7) ◽  
pp. 1627-1635 ◽  
Author(s):  
C. Petri ◽  
T. Warneke ◽  
N. Jones ◽  
T. Ridder ◽  
J. Messerschmidt ◽  
...  
Keyword(s):  
High Resolution ◽  
A Priori ◽  
Absorption Spectrometry ◽  
Total Carbon ◽  
High Spectral Resolution ◽  
Low Resolution ◽  
Average Deviation ◽  
Solar Absorption ◽  
Fourier Transform Spectrometry ◽  
The Difference

Abstract. Throughout the last few years solar absorption Fourier Transform Spectrometry (FTS) has been further developed to measure the total columns of CO2 and CH4. The observations are performed at high spectral resolution, typically at 0.02 cm−1. The precision currently achieved is generally better than 0.25%. However, these high resolution instruments are quite large and need a dedicated room or container for installation. We performed these observations using a smaller commercial interferometer at its maximum possible resolution of 0.11 cm−1. The measurements have been performed at Bremen and have been compared to observations using our high resolution instrument also situated at the same location. The high resolution instrument has been successfully operated as part of the Total Carbon Column Observing Network (TCCON). The precision of the low resolution instrument is 0.32% for XCO2 and 0.46% for XCH4. A comparison of the measurements of both instruments yields an average deviation in the retrieved daily means of &amp;leq;0.2% for CO2. For CH4 an average bias between the instruments of 0.47% was observed. For test cases, spectra recorded by the high resolution instrument have been truncated to the resolution of 0.11 cm−1. This study gives an offset of 0.03% for CO2 and 0.26% for CH4. These results indicate that for CH4 more than 50% of the difference between the instruments results from the resolution dependent retrieval. We tentatively assign the offset to an incorrect a-priori concentration profile or the effect of interfering gases, which may not be treated correctly.

scholarly journals Lunar Image Fusion using Wavelet Transform

2013 ◽  
pp. 211-215
Author(s):  
Dr.Vani. K ◽  
Anto. A. Micheal
Keyword(s):  
High Resolution ◽  
Image Fusion ◽  
Spatial Resolution ◽  
Spectral Resolution ◽  
Lunar Surface ◽  
High Spatial Resolution ◽  
Multispectral Image ◽  
High Spectral Resolution ◽  
Low Resolution ◽  
Mineral Mapping

This paper is an attempt to combine high resolution panchromatic lunar image with low resolution multispectral lunar image to produce a composite image using wavelet approach. There are many sensors that provide us image data about the lunar surface. The spatial resolution and spectral resolution is unique for each sensor, thereby resulting in limitation in extraction of information about the lunar surface. The high resolution panchromatic lunar image has high spatial resolution but low spectral resolution; the low resolution multispectral image has low spatial resolution but high spectral resolution. Extracting features such as craters, crater morphology, rilles and regolith surfaces with a low spatial resolution in multispectral image may not yield satisfactory results. A sensor which has high spatial resolution can provide better information when fused with the high spectral resolution. These fused image results pertain to enhanced crater mapping and mineral mapping in lunar surface. Since fusion using wavelet preserve spectral content needed for mineral mapping, image fusion has been done using wavelet approach.

3. LYMAN Technical Description

1988 ◽  
Vol 7 (3) ◽  
pp. 290-334
Keyword(s):  
High Resolution ◽  
Spectral Range ◽  
Spectral Resolution ◽  
Grazing Incidence ◽  
Field Of View ◽  
Type Ii ◽  
Low Resolution ◽  
Service Module ◽  
Technical Description ◽  
Extreme Uv

The LYMAN Observatory payload is mounted on a service module which which offers pointing, power and telemetry and which has substantial commonality with the SOHO concept. The payload consists of a Wolter-Schwartzschild Type II Grazing Incidence telescope with monolithic primary and secondary elements feeding far-UV and extreme-UV spectrographs. It is designed to offer an effective collecting area of greater than 10 cm2 over a limited field of view with a spectral resolution on astronomical targets of 30000 in the prime ( λ900 - 1250 Å ) spectral range. This will allow high-resolution observations on sources as faint as 15 mag. LYMAN will also be capable of high resolution observations up to 1800Å, and will offer low-resolution spectroscopy in the extreme-UV down to about 100Å.

Spectral Observations of the Extreme Ultraviolet Astronomical Background Radiation

1988 ◽  
Vol 102 ◽  
pp. 63-66
Author(s):  
S. Labov ◽  
S. Bowyer
Keyword(s):  
Interstellar Medium ◽  
Background Radiation ◽  
Extreme Ultraviolet ◽  
Grazing Incidence ◽  
Sounding Rocket ◽  
Interstellar Space ◽  
Spectral Measurements ◽  
Interstellar Gas ◽  
Hot Plasma ◽  
Far Ultraviolet

AbstractObservations in the far ultraviolet and soft x-ray bands suggest that the interstellar medium contains several components of high temperature gas (105to 106K). If large volumes of local interstellar space are filled with this hot plasma, emission lines will be produced in the extreme ultraviolet (EUV). Diffuse EUV radiation, however, has only been detected with photometric instruments; no spectral measurements exist below 520Å. We have designed a unique grazing incidence spectrometer to study the diffuse emission between 80 and 650Å with 10 to 30Å resolution. This instrument was successfully flown on a sounding rocket in April of 1986 and a preliminary analysis reveals several features. In addition to the expected interplanetary He I 584Å emission and the geocoronal He II 304Å emission, other features appear which may originate in the hot ionized interstellar gas. These features are discussed along with the possible implications to the hot phase of the interstellar medium.

scholarly journals Self-Dictionary Regression for Hyperspectral Image Super-Resolution

2018 ◽  
Vol 10 (10) ◽  
pp. 1574 ◽  
Author(s):  
Dongsheng Gao ◽  
Zhentao Hu ◽  
Renzhen Ye
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Spectral Resolution ◽  
Cross Correlation ◽  
Hyperspectral Image ◽  
High Spatial Resolution ◽  
Super Resolution ◽  
High Spectral Resolution ◽  
Low Resolution ◽  
Image Super Resolution

Due to sensor limitations, hyperspectral images (HSIs) are acquired by hyperspectral sensors with high-spectral-resolution but low-spatial-resolution. It is difficult for sensors to acquire images with high-spatial-resolution and high-spectral-resolution simultaneously. Hyperspectral image super-resolution tries to enhance the spatial resolution of HSI by software techniques. In recent years, various methods have been proposed to fuse HSI and multispectral image (MSI) from an unmixing or a spectral dictionary perspective. However, these methods extract the spectral information from each image individually, and therefore ignore the cross-correlation between the observed HSI and MSI. It is difficult to achieve high-spatial-resolution while preserving the spatial-spectral consistency between low-resolution HSI and high-resolution HSI. In this paper, a self-dictionary regression based method is proposed to utilize cross-correlation between the observed HSI and MSI. Both the observed low-resolution HSI and MSI are simultaneously considered to estimate the endmember dictionary and the abundance code. To preserve the spectral consistency, the endmember dictionary is extracted by performing a common sparse basis selection on the concatenation of observed HSI and MSI. Then, a consistent constraint is exploited to ensure the spatial consistency between the abundance code of low-resolution HSI and the abundance code of high-resolution HSI. Extensive experiments on three datasets demonstrate that the proposed method outperforms the state-of-the-art methods.

scholarly journals The FUSE Mission: Atomic Data Needs in the 900–1200 Å Spectral Region

2002 ◽  
Vol 12 ◽  
pp. 79-81
Author(s):  
Kenneth R. Sembach
Keyword(s):  
High Resolution ◽  
Solar System ◽  
Interstellar Medium ◽  
Absorption Line ◽  
Ground State ◽  
Spectral Region ◽  
Theoretical Calculations ◽  
Oscillator Strengths ◽  
Atomic Data ◽  
Far Ultraviolet

AbstractThe Far Ultraviolet Spectroscopic Explorer (FUSE) is presently producing high resolution (R ∼ 20,000) absorption-line spectra of astronomical objects ranging from Solar System planets to quasars. The 900-1200 Å spectral region observed by FUSE is exceedingly rich in atomic and molecular transitions arising out of the ground state. It is already clear from early FUSE observations that the atomic data (e.g., oscillator strengths) for some transitions are considerably different than those predicted by theoretical calculations. I briefly describe the most pressing oscillator strength needs in this wavelength range for studies of the interstellar medium.

scholarly journals Remote sensing of CO<sub>2</sub> and CH<sub>4</sub> using solar absorption spectrometry with a commercial low resolution spectrometer

2012 ◽  
Vol 5 (1) ◽  
pp. 245-269 ◽  
Author(s):  
C. Petri ◽  
T. Warneke ◽  
N. Jones ◽  
T. Ridder ◽  
J. Messerschmidt ◽  
...  
Keyword(s):  
High Resolution ◽  
A Priori ◽  
Absorption Spectrometry ◽  
Total Carbon ◽  
High Spectral Resolution ◽  
Low Resolution ◽  
Average Deviation ◽  
Solar Absorption ◽  
Fourier Transform Spectrometry ◽  
The Difference

Abstract. Throughout the last few years solar absorption Fourier Transform Spectrometry (FTS) has been further developed to measure the total columns of CO2 and CH4. The observations are performed at high spectral resolution, typically at 0.02 cm−1. The precision achieved is actually generally better than 0.25%. However, these high resolution instruments are quite large and need a dedicated room or container for installation. We performed these observations using a smaller commercial interferometer at its maximum possible resolution of 0.11 cm−1. The measurements have been performed at Bremen and have been compared to observations using our high resolution instrument also situated at the same location. The high resolution instrument has been successfully operated as part of the Total Carbon Column Observing Network (TCCON). The precision of the low resolution instrument is 0.32% for XCO2 and 0.46% for XCH4. A comparison of the measurements of both instruments yields an average deviation in the retrieved daily means of &amp;leq;0.2% for CO2. For CH4 an average bias between the instruments of 0.46% was observed. For test cases, spectra recorded by the high resolution instrument have been truncated to the resolution of 0.11 cm−1. This study gives an offset of 0.03% for CO2 and 0.26% for CH4. These results indicate that for CH4 more than 50% of the difference between the instruments results from the resolution dependant retrieval. We tentatively assign the offset to an incorrect a-priori concentration profile or the effect of interfering gases, which may not be treated correctly.

scholarly journals FUSE and the Quest for High-Resolution Spectroscopy in the Far Ultraviolet

2005 ◽  
Vol 13 ◽  
pp. 793-795
Author(s):  
H. Warren Moos
Keyword(s):  
High Resolution ◽  
Spectral Region ◽  
Velocity Structure ◽  
Ionic Species ◽  
Resolving Power ◽  
High Resolution Spectroscopy ◽  
Gas Velocity ◽  
The Status ◽  
Instrumental Resolution ◽  
Far Ultraviolet

AbstractThe Far Ultraviolet Spectroscopic Explorer (FUSE) instrument covers the spectral range 912-1187 Å with a resolving power of 15,000 to 20,000. This spectral region provides unique access for the study of many atomic and ionic species found in the interstellar medium, intergalactic medium, stars, and extragalactic objects. This paper summarizes the status of the mission and then discusses the need for higher resolution spectroscopy. Although the FUSE instrumental resolution is sufficient to separate most species, it usually it is not adequate for analyzing the gas velocity structure in detail. Implications for future missions are discussed.

scholarly journals D/H-Ratio: Observations with ORFEUS II

1997 ◽  
Vol 166 ◽  
pp. 75-78
Author(s):  
M. Gölz ◽  
N. Kappelmann ◽  
I. Appenzeller ◽  
J. Barnstedt ◽  
A. Fromm ◽  
...  
Keyword(s):  
High Resolution ◽  
Spectral Range ◽  
Spectral Resolution ◽  
Column Density ◽  
Line Of Sight ◽  
A Value ◽  
Hydrogen Column Density ◽  
Far Ultraviolet ◽  
First Time

AbstractDuring the second flight of the ORFEUS-SPAS satellite (Nov./Dec. 96) high resolution (λ/∆λ = 10,000) Echelle-spectra of BD+28° 4211 in the wavelength regime 912–1400 Å have been taken. Deuterium can be clearly identified in the ORFEUSII Echelle-spectra of this star. For the first time it was possible to take spectra of faint, not redshifted objects in the far ultraviolet with a sufficient spectral resolution to study the deuterium column density in the whole spectral range of the Lyman-series down to the Lyman-limit. We obtained a value of log(ND) = 14.7 (±0.3) towards BD+28° 4211. The hydrogen column density has been determined using ORFEUS Echelle- and IUE-spectra of Ly-α (log(NH) = 19.8 (±0.2)). Thus a value of 8 × 10−6 can be obtained for the D/H-ratio on the line-of-sight towards BD+28° 4211.

scholarly journals Domain Transfer Learning for Hyperspectral Image Super-Resolution

2019 ◽  
Vol 11 (6) ◽  
pp. 694 ◽  
Author(s):  
Xiaoyan Li ◽  
Lefei Zhang ◽  
Jane You
Keyword(s):  
High Resolution ◽  
Transfer Learning ◽  
Spatial Resolution ◽  
Hyperspectral Image ◽  
Super Resolution ◽  
High Spectral Resolution ◽  
Low Resolution ◽  
Image Super Resolution ◽  
Domain Transfer ◽  
Domain Transfer Learning

A Hyperspectral Image (HSI) contains a great number of spectral bands for each pixel; however, the spatial resolution of HSI is low. Hyperspectral image super-resolution is effective to enhance the spatial resolution while preserving the high-spectral-resolution by software techniques. Recently, the existing methods have been presented to fuse HSI and Multispectral Images (MSI) by assuming that the MSI of the same scene is required with the observed HSI, which limits the super-resolution reconstruction quality. In this paper, a new framework based on domain transfer learning for HSI super-resolution is proposed to enhance the spatial resolution of HSI by learning the knowledge from the general purpose optical images (natural scene images) and exploiting the cross-correlation between the observed low-resolution HSI and high-resolution MSI. First, the relationship between low- and high-resolution images is learned by a single convolutional super-resolution network and then is transferred to HSI by the idea of transfer learning. Second, the obtained Pre-high-resolution HSI (pre-HSI), the observed low-resolution HSI, and high-resolution MSI are simultaneously considered to estimate the endmember matrix and the abundance code for learning the spectral characteristic. Experimental results on ground-based and remote sensing datasets demonstrate that the proposed method achieves comparable performance and outperforms the existing HSI super-resolution methods.

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